Tìm x:
a ) x + 100 = 150
b ) x + 50 = 45 x 2
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 2:
a: Ta có: \(2x+79=x+45\)
nên 2x-x=45-79
hay x=-24
b: Ta có: \(15-\left(x+7\right)=\left(x-8\right)+22\)
\(\Leftrightarrow8-x-x-14=0\)
\(\Leftrightarrow2x=22\)
hay x=11
a.\(x+\dfrac{4}{7}=\dfrac{38}{21}\)
\(x=\dfrac{38}{21}-\dfrac{4}{7}\)
\(x=\dfrac{38}{21}-\dfrac{12}{21}=\dfrac{26}{21}\)
b.\(x-\dfrac{1}{3}=\dfrac{7}{45}:\dfrac{2}{15}\)
\(x-\dfrac{1}{3}=\dfrac{7}{6}\)
\(x=\dfrac{7}{6}+\dfrac{1}{3}\)
\(x=\dfrac{7}{6}+\dfrac{2}{6}=\dfrac{9}{6}\)
\(a,50\%x-0,2+x=\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{1}{2}x-0,2+x=\dfrac{4}{5}\)
\(\Leftrightarrow\dfrac{1}{2}x+x=\dfrac{4}{5}+0,2\)
\(\Leftrightarrow\dfrac{3}{2}x=\dfrac{4}{5}+\dfrac{1}{5}\)
\(\Leftrightarrow\dfrac{3}{2}x=1\)
\(\Leftrightarrow x=\dfrac{2}{3}\)
\(b,\left(x-\dfrac{3}{4}\right):\dfrac{1}{2}+\dfrac{3}{2}=\dfrac{25}{2}\)
\(\Leftrightarrow\left(x-\dfrac{3}{4}\right).2=\dfrac{25}{2}-\dfrac{3}{2}\)
\(\Leftrightarrow\left(x-\dfrac{3}{4}\right).2=\dfrac{22}{2}\)
\(\Leftrightarrow x-\dfrac{3}{4}=11:2\)
\(\Leftrightarrow x=\dfrac{11}{2}+\dfrac{3}{4}\)
\(\Leftrightarrow x=\dfrac{25}{4}\)
a; Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:
\(\dfrac{x}{7}=\dfrac{y}{4}=\dfrac{x-y}{7-4}=\dfrac{12}{3}=4\)
Do đó: x=28; y=16
a: x=2/3-4/5=10/15-12/15=-2/15
b: 1/2-x=7/12
=>x=1/2-7/12=-1/12
c: =>7/2:x=-7/2
=>x=-1
d: =>1/6x=3/8-5/2=3/8-20/8=-17/8
=>x=-17/8*6=-102/8=-51/4
e: =>1,5x=-1,5
=>x=-1
\(a,\Leftrightarrow x\left(12+7+1\right)=100\)
\(\Leftrightarrow x.20=100\)
\(\Leftrightarrow x=50\)
\(b,\Leftrightarrow x\left(4+3\right)=1071\)
\(\Leftrightarrow7x=1071\)
\(\Leftrightarrow x=153\)
\(c,\Leftrightarrow x-60720=960\times5\)
\(\Leftrightarrow x-60720=4800\)
\(\Leftrightarrow x=4800+60720\)
\(\Leftrightarrow x=65520\)
\(d,\Leftrightarrow x:4=22850-11250\)
\(\Leftrightarrow x:4=11600\)
\(\Leftrightarrow x=46400\)
a. 2x + 70 = 74
<=> 2x = 4
<=> x = 2
b. 120 - \(\dfrac{4x}{2}\) = 80
<=> 120 - 2x = 80
<=> 120 - 80 = 2x
<=> 2x = 40
<=> x = 20
c. (3x + 5)2 = 400
<=> \(|3x+5|=\sqrt{400}\)
<=> \(|3x+5|=20\)
<=> \(\left[{}\begin{matrix}3x+5=20\\3x+5=-20\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=\dfrac{-25}{3}\end{matrix}\right.\)
a: Ta có: \(71-\left(x+33\right)=26\)
\(\Leftrightarrow x+33=45\)
hay x=12
b: Ta có: \(\left(x+73\right)-26=76\)
\(\Leftrightarrow x+73=102\)
hay x=29
c: Ta có: \(45-\left(x+9\right)=6\)
\(\Leftrightarrow x+9=39\)
hay x=30
a) 71 - ( 33 + x ) = 26
(33 + x ) = 71 -26
33 + x = 45
x = 45 - 33 = 12
b) ( x + 73 ) - 26 = 76
( x + 73 ) = 102
x = 102 - 73 = 29
c) 45 - ( x + 9 ) = 6
( x + 9 ) = 45 - 6 = 39
x = 39 - 9 = 30
d) 89 - ( 73 - x ) = 20
73 - x = 89 - 20
73 - x = 69
x = 73 - 69 = 4
e) 4(x+41) = 400
x + 41 = 400 : 4 = 100
x = 100 - 41 = 59
f) 11(x-9 ) = 77
x - 9 = 77 : 11 = 7
x = 7 + 9 = 16
g) x + 7 = 25 + 13 = 38
x = 38 - 7 = 31
h) x + 4 = 198 - 120 = 78
x = 78 - 4 = 74
i) x - 9 = 350 : 5 = 70
x = 70 + 9 = 79
j) 2x - 49 = 5 . 9 = 45
2x = 45 + 49 = 94
x = 94 : 2 = 47
k) 25 + 3( x - 8 ) = 106
3(x-8 ) = 106 - 25 = 81
x - 8 = 81 : 3 = 27
x = 27 +8= 35
l) 9( x + 4 ) - 25 = 20
9( x + 4 ) = 20 + 25 = 45
x + 4 =45 : 9 = 5
x = 5 - 4 = 1
m) 200 - ( 2x + 6 ) = 64
2x + 6 = 200 - 64 = 136
2x = 136 - 6 = 130
x = 130 : 2 = 65
Bài 2: Tính bằng cách thuận tiện nhất:
a) 239 x 45 + 55 x 239 b) 459 x 107 – 7 x 459
= 239 x (45 + 55) = 459 x (107 - 7)
= 239 x 100 = 495 x 100
= 23900 = 49500
c) 784 x 98 +784 +784 d) 982 x 1003 – 982 x2 – 982
= 784 x 98 + 784 x 2 = 982 x (1003 -2 -1)
= 784 x (98+2) = 982 x 1000
= 784 x 100 = 982000
= 78400
x+100=150
x=150-100
x=50
x+50=45x2
x+50=90
x=90-50
x=40
tk mk mk tk lại
thank you
(^_^)
Tìm x:
a ) x + 100 = 150
x = 150 - 100
x = 50
b ) x + 50 = 45 x 2
x + 50 = 90
x = 90 - 50
x = 40