tìm x
x* 16 -x = 480
(2 4/5* x -50 ): 2/3 = 51
ai làm nhanh mình tcik cho
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a) \(2.\left(x+\frac{2}{5}\right)+1\frac{1}{4}=\frac{11}{20}\)
\(2.\left(x+\frac{2}{5}\right)+\frac{5}{4}=\frac{11}{20}\)
\(2.\left(x+\frac{2}{5}\right)=\frac{-7}{10}\)
\(x+\frac{2}{5}=\frac{-7}{20}\)
\(x=\frac{-13}{20}\)
Vậy \(x=\frac{-13}{20}\)
b)\(x-1\frac{1}{8}-\frac{2}{3}x-\frac{5}{6}x=75\%\)
\(\left(x-\frac{2}{3}x-\frac{5}{6}x\right)-\frac{9}{8}=\frac{3}{4}\)
\(\frac{-1}{2}x-\frac{9}{8}=\frac{3}{4}\)
\(\frac{-1}{2}x=\frac{15}{8}\)
\(x=\frac{-15}{4}\)
Vậy \(x=\frac{-15}{4}\)
a) 456 + ( x - 357 ) = 1362
x - 357=1362-456
x - 357=906
x=906+357
x=1263
b) ( 2345 - x) - 183 = 2014
2345 - x=2014+183
2345 - x=2197
x=2345-2197
x=148
c) ( x - 2005 ) . 2006 = 0
x - 2005 =0:2006
x - 2005 =0
x=0+2005
x=2005
d) 480 + 45 . 4 = ( x + 125) : 5 + 260
480 + 180 = ( x + 125) : 5 + 260
660=( x + 125) : 5 + 260
( x + 125) : 5 + 260=660
( x + 125) : 5=660-260
( x + 125) : 5=400
x + 125 =400.5
x + 125 =2000
x=20000-125
x=1975
e) 2005 . ( x - 2006) =2005
x - 2006=2005:2005
x - 2006=1
x=1+2006
x=2007
g) [( x + 50) . 50 - 50] : 50 = 50
( x + 50) . 50 - 50=50.50
( x + 50) . 50 - 50=2500
( x + 50) . 50=2500+50
( x + 50) . 50=2550
x + 50=2550:50
x + 50=51
x=51-50
x=1
Bạn Huyền ơi ở chỗ câu d mình ko hiểu tại sao 400.5=2000 mà ở dưới lại ghi 20000-125
a: \(\Leftrightarrow x\in\left\{1;-1;2;-2;3;-3;4;-4;6;-6;9;-9;12;-12;18;-18;36;-36\right\}\)
mà -3<x<30
nên \(x\in\left\{-2;-1;1;2;3;4;6;9;12;18\right\}\)
b: \(\Leftrightarrow x\in\left\{0;4;-4;8;-8;12;-12;...\right\}\)
mà -16<=x<20
nên \(x\in\left\{-16;-12;-8;-4;0;4;8;12;16\right\}\)
c: \(\Leftrightarrow x-1+4⋮x-1\)
\(\Leftrightarrow x-1\in\left\{1;-1;2;-2;4;-4\right\}\)
hay \(x\in\left\{2;0;3;-1;5;-3\right\}\)
d: \(\Leftrightarrow2x+4-5⋮x+2\)
\(\Leftrightarrow x+2\in\left\{1;-1;5;-5\right\}\)
hay \(x\in\left\{-1;-3;3;-7\right\}\)
Bài 1:
Ta có:
\(y-x=25\Rightarrow y=25+x\)
Mà \(7x=4y\Rightarrow7x=4\cdot\left(25+x\right)\)
\(7x=100+4x\)
\(\Rightarrow7x-4x=100\)
\(3x=100\)
\(x=\frac{100}{3}\)
bài 1 :
Ta có: 7x=4y ⇔ x/4=y/7
áp dụng tính chất dãy tỉ số bằng nhau ta có
x/4=y/7=(y-x)/(7-4)=100/3
⇒x= 4 x 100/3=400/3 ; y = 7 x 100/3=700/3
bài 2
ta có x/5 = y/6 ⇔ x/20=y/24
y/8 = z/7 ⇔ y/24=z/21
⇒x/20=y/24=z/21
ADTCDTSBN(bài 1 có)
x/20=y/24=z/21=(x+y)/(20+24)=69/48=23/16
⇒x= 20 x 23/16 = 115/4
y= 24x 23/16=138/2
z=21x23/16=483/16
a) \(x+215=480\)
\(x=480-215\)
\(x=265\)
b) \(725-x=185:5\)
\(725-x=37\)
\(x=725-37\)
\(x=688\)
c) \(x\times\dfrac{1}{3}+x\times\dfrac{4}{3}=\dfrac{2}{3}\)
\(x\times\left(\dfrac{1}{3}+\dfrac{4}{3}\right)=\dfrac{2}{3}\)
\(x\times\dfrac{5}{3}=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}:\dfrac{5}{3}=\dfrac{2}{3}\times\dfrac{3}{5}\)
\(x=\dfrac{2}{5}\)
d) \(\left(\dfrac{13}{5}+\dfrac{2}{3}\right):x=5\)
\(\dfrac{49}{15}:x=5\)
\(x=\dfrac{49}{15}:5=\dfrac{49}{15}\times\dfrac{1}{5}\)
\(x=\dfrac{49}{75}\)
a)x + 215 = 480
x = 480 - 215
x = 265
b) 725 - x = 185 : 5
725 - x = 37
x = 725 - 37
x = 688
X x 16 - X = 480
= >X x 16 - X x 1 = 480
=> X x (16 - 1) = 480
=> X x 15 = 480
=> X = 480 : 15
=> x = 32
B/
24/5 x X - 50= 51 x 2/3
(24/5 x X )- 50 = 34
24/5 x X = 34 + 50
24/5 x X = 84
X = 84 : 24/5
X = 17.5
\(x\cdot16-x=480\)
\(x\cdot16-x\cdot1=480\)
\(x\cdot\left(16-1\right)=480\)
\(x\cdot15=480\)
\(x=480:15\left(...\right)\)
\(x=32\)
\(\left(\frac{24}{5}\cdot x-50\right):\frac{2}{3}=51\)
\(\frac{24}{5}\cdot x-50=51\cdot\frac{2}{3}\)
\(\frac{24}{5}\cdot x-50=34\)
\(\frac{24}{5}\cdot x=34+50\)
\(\frac{24}{5}\cdot x=84\)
\(x=84:\frac{24}{5}\left(...\right)\)
\(x=17,5\)