Bài 1: Tính diện tích hình chữ nhật biết độ dài hai cạnh là 94,54m và 21,0...">
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a) −15<11000−15<11000                         ...
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a) &#x2212;15&lt;11000" role="presentation" style="border:0px; direction:ltr; display:inline-block; float:none; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; text-align:left; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">15<11000                            

b) 267&#x2212;268&gt;&#x2212;13471343" role="presentation" style="border:0px; direction:ltr; display:inline-block; float:none; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; text-align:left; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">267268>13471343

c) &#x2212;1338&lt;29&#x2212;88" role="presentation" style="border:0px; direction:ltr; display:inline-block; float:none; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; text-align:left; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">1338<2988

d) &#x2212;1831=&#x2212;181818313131" role="presentation" style="border:0px; direction:ltr; display:inline-table; float:none; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; text-align:left; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">

 
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15 tháng 10 2016

Ta có:

\(\frac{x}{7}+\frac{y}{11}+\frac{z}{13}=0,\left(946053\right)\)

\(\Rightarrow\frac{x}{7}+\frac{y}{11}+\frac{z}{13}=0,\left(000001\right).946053\)

\(\Rightarrow\frac{11.13.x}{7.11.13}+\frac{7.13.y}{7.11.13}+\frac{7.11.z}{7.11.13}=\frac{946053}{999999}=\frac{946053}{7.11.13.999}\)

\(\Rightarrow11.13.x+7.13.y+7.11.z=\frac{946053}{999}=947\)

\(\Rightarrow7.\left(13.y+11.z\right)=947-143.x\)

Vì 7.(13y + 11z) > 0 do y; z \(\in\) N* nên 947 - 143.x > 0

hay 143x < 947 hay \(x\le6\)

\(\Rightarrow x\in\left\{1;2;3;4;5;6\right\}\)

Thử với từng giá trị của x ta thấy chỉ có x = 3 thỏa mãn \(947-143x⋮7\)

+ Với x = 3 thì 13y + 11z = 74 => 11z = 74 - 13y

Vì 11z > 0 do z \(\in\) N* nên 74 - 13y > 0

hay 13y < 74 hay y < 6

\(\Rightarrow y\in\left\{1;2;3;4;5\right\}\)

Thử với từng trường hợp của y ta thấy chỉ có y = 4 thỏa mãn \(74-13y⋮11\)

=> z = (74 - 13.4) : 11 = 2

Vậy x = 3; y = 4; z = 2

 

15 tháng 10 2016

DỄ NHỈ LÀM CÓ 5 DÒNG

Bài 1: Tìm x:a) x15=−23,5x15=−23,5b) 16x=x2516x=x25c) 0,50,7=−0,15x0,50,7=−0,15xBài 2: Lập tất cả các tỉ lệ thức từ bốn số sau :-25; -2; 4; 50Bài 3: Tìm x, y, z:a) x5=y25x5=y25 và x+ y = 60b) 5x=3y5x=3y và x-y = -5c) x2=y4=z6x2=y4=z6 và y+z-x = 8d) x3=y4;y6=z8x3=y4;y6=z8 và x + y - z = 50e) x3=y4=z5x3=y4=z5 và 2x + 3y + 5z = 86f) x : y : z = 2 : 5 : 7 và x + y + z = -28g) x3=y7=z2x3=y7=z2 và 2x2+y2+3z2=3162x2+y2+3z2=316P/s: Giúp mình với...
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Bài 1: Tìm x:

a) x15=&#x2212;23,5" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">x15=23,5

b) 16x=x25" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">16x=x25

c) 0,50,7=&#x2212;0,15x" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">0,50,7=0,15x

Bài 2: Lập tất cả các tỉ lệ thức từ bốn số sau :

-25; -2; 4; 50

Bài 3: Tìm x, y, z:

a) x5=y25" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">x5=y25 và x+ y = 60

b) 5x=3y và x-y = -5

c) x2=y4=z6" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">x2=y4=z6 và y+z-x = 8

d) x3=y4;y6=z8" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">x3=y4;y6=z8 và x + y - z = 50

e) x3=y4=z5" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">x3=y4=z5 và 2x + 3y + 5z = 86

f) x : y : z = 2 : 5 : 7 và x + y + z = -28

g) x3=y7=z2" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">x3=y7=z2  2x2+y2+3z2=316" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-block; float:none; font-size:20.34px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">2x2+y2+3z2=316

P/s: Giúp mình với các bạn, mình đg rất cần gấp. Thank you

 

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Bài 1: Tìm xx, biết:a) 12−|x−3|=5x+812−|x−3|=5x+8                                                                         b) (√x+3)10=1024.1252.252(x+3)10=1024.1252.252c) 3−0,2x5=715+1,4x3−0,2x5=715+1,4x                                         d) (6427)x=4.59.710−511.79359.4Bài 2: Tính A = 123.1212.5−224.33752.114−302.115123.1212.5−224.33752.114−302.115B...
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Bài 1: Tìm x, biết:

  1. a) |x&#x2212;3|=5x+8" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-block; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">12|x3|=5x+8                                                                         
  2. b) (x+3)10=1024.1252.252" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-table; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">(x+3)10=1024.1252.252
  3. c) 30,2x5=715+1,4x                                         
  4. d) (6427)x=4.59.710&#x2212;511.79359.4" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-block; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">

Bài 2: Tính

A = 123.1212.5&#x2212;224.33752.114&#x2212;302.115" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-block; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">123.1212.5224.33752.114302.115

B = 

  1. a) |x&#x2212;2|=|2x+1|" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-block; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">|x2|=|2x+1|                                                                       
  2. b) 3(x+12)12(4x23)=56
  3. c) 

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