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Tìm số nguyên x, biết:
1) -16 + 23 + x = - 16
7+x=-16
x=-16-7
x=-23
2) 2x – 35 = 15
2x=15+35
2x=50
x=50:2
x=25
3) 3x + 17 = 12
3x=12-17
3x=-5
x=-5/3
4) (2x – 5) + 17 = 6
2x-5=6-17
2x-5=-11
2x=-11+5
2x=-6
x=-6:2
x=-3
5) 10 – 2(4 – 3x) = -4
2(4-3x)=10-(-4)
2(4-3x)=14
4-3x=14:2
4-3x=7
3x=4-7
3x=-3
x=-3:3
x=-1
6) - 12 + 3(-x + 7) = -18
3(-x+7)=-18-(-12)
3(x+7)=-6
x+7=-6:3
x+7=-2
x=-2-7
x=-9
Bạn chỉ gửi 1 bài thôi chứ nhiều quá làm mỏi tay lắm
Làm bài 1 trước
\(4\cdot(-5)^2+2\cdot(-5)-20\)
\(=4\cdot25+2\cdot(-5)-20\)
\(=100+(-10)-20=100-30=70\)
\(35\cdot(14-10)-14\cdot(35-10)\)
\(=35\cdot14-35\cdot10-14\cdot35-14\cdot10\)
\(=35\cdot14-14\cdot35-35\cdot10-14\cdot10\)
\(=35\cdot10-14\cdot10=(35-14)\cdot10=210\)
\(3\cdot(-5)^2+2\cdot(-5)-20\)
Tương tự như ở câu trên
\(34\cdot(15-10)-15\cdot(34-10)\)
Tương tự như câu thứ 2
Câu cuối tự làm
a, 7\(x\).(\(x\) - 10) = 0
\(\left[{}\begin{matrix}7x=0\\x-10=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=0\\x=10\end{matrix}\right.\)
Vậy \(x\in\) {0; 10}
b, 17.(3\(x\) - 6).(2\(x\) - 18) = 0
\(\left[{}\begin{matrix}3x-6=0\\2x-18=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}3x=6\\2x-18=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=6:3\\x=18:2\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=2\\x=9\end{matrix}\right.\)
a) x/7 = 6/21
x/7 = 2/7
=>x=2
b)2/3x -1/2=1/10
2/3x = 1/10+1/2
2/3x = 3/5
x=3/5:2/3
x=9/10
c)1/4+1/3 : x = -5
d)3x+17=2
đ)2/3x +1/4 =7/12
2x+3/10= 11/6 . 6/11
x : 4 1/3 = -2,5
a) ( 2x - 5 ) + 17 = 6
( 2x - 5 ) = 6 - 17
( 2x - 5 ) = - 11
2x = - 11 + 5
2x = - 6
x = - 6 : 2
x = - 3
Vậy x = - 3
b) 10 - 2( 4 - 3x ) = - 4
2 ( 4 - 3x ) = 10 - ( -4 )
2 ( 4 -3x ) = 10 + 4 = 14
4 - 3x = 14 : 2 = 7
3x = 4 - 7 = -3
x = -3 : 3
x = - 1
Vậy x = - 1
c ) - 12 + 3 ( - x + 7 ) = - 18
3 ( - x + 7 ) = - 18 - ( - 12 )
3 ( - x + 7) = - 18 + 12 = - 6
( - x + 7 ) = - 6 : 3
- x + 7 = - 2
- x = - 2 - 7
- x = - 9
=> x = 9
Vậy x = 9
d) 24 : ( 3x - 2 ) = - 3
3x - 2 = 24 : ( - 3 )
3x - 2 = - 8
3x = - 8 + 2
3x = - 6
x = - 6 : 3
x = - 2
Vậy x = - 2
e ) - 45 : [ 5 . ( - 3 - 2x )] = 3 ( câu này bạn viết thiếu đe nha , làm mình tính mãi không ra )
5 . ( - 3 - 2x ) = - 45 : 3
5 . ( -3 - 2x ) = - 15
- 3 - 2x = - 15 : 5
- 3 - 2x = - 3
2x = - 3 - ( - 3 )
2x = - 3 + 3
2x = 0
=> x = 0
Vậy x = 0
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a, (2x - 5) + 17 = 6
=> 2x - 5 + 17 = 6
=> 2x = 6 - 17 + 5
=> 2x = -6
=> x = -3
vậy_
a, (2x - 5) + 17 = 6
2x - 5 = 6 - 17
2x - 5 = -11
2x = -11 + 5
2x = -6
x = -6 : 2 = -3
b) -12 + 3.(-x + 7) = -18
3.(-x + 7) = -18 + 12
3.(-x + 7) = -6
-x + 7 = -6:3
-x + 7 = -2
-x = -2 - 7
-x = -9
x = 9
a)=2
b)=0.3333333333
c)=9
d)= chua tinh
e)=33
g)=5
tk minh nha ban nha
a) (2x-5)+17=16
2x-5=16-17
2x-5=-1
2x=-1+5
2x=4
x=4:2
x=2
b) 10-2.(4-3x)=-4
2.(4-3x)=10--4
2.(4-3x)=14
4-3x=14:2
4-3x=7
3x=4-7
3x=-3
x=-3:3
x=-1
a) \(\dfrac{x}{5}+\dfrac{1}{2}=\dfrac{6}{10}\\ \dfrac{x}{5}+\dfrac{1}{2}=\dfrac{3}{5}\\ \dfrac{x}{5}=\dfrac{3}{5}-\dfrac{1}{2}\\ \dfrac{x}{5}=\dfrac{6}{10}-\dfrac{5}{10}\\ \dfrac{x}{5}=\dfrac{1}{10}\\ \dfrac{2x}{10}=\dfrac{1}{10}\\ \Rightarrow2x=1\\ x=1:2\\ x=0,5=\dfrac{1}{2}\)
b) \(x+\dfrac{3}{15}=\dfrac{1}{3}\\ x=\dfrac{1}{3}-\dfrac{3}{15}\\ x=\dfrac{5}{15}-\dfrac{3}{15}\\ x=\dfrac{2}{15}\)
c) \(x-\dfrac{12}{4}=\dfrac{1}{2}\\ x-3=\dfrac{1}{2}\\ x=\dfrac{1}{2}+3\\ x=\dfrac{1}{2}+\dfrac{6}{2}\\ x=\dfrac{7}{2}\)
d) \(\dfrac{1}{2}x+\dfrac{1}{2}=\dfrac{5}{2}\\ \dfrac{1}{2}x=\dfrac{5}{2}-\dfrac{1}{2}\\ \dfrac{1}{2}x=2\\ x=2:\dfrac{1}{2}\\ x=4\)
a. \(\dfrac{2x+5}{10}=\dfrac{6}{10}\Leftrightarrow2x=1\Leftrightarrow x=\dfrac{1}{2}\)
b. \(\dfrac{15x+3}{15}=\dfrac{5}{15}\Leftrightarrow15x=2\Leftrightarrow x=\dfrac{2}{15}\)
c. \(\dfrac{4x-12}{4}=\dfrac{2}{4}\Leftrightarrow4x=14\Leftrightarrow x=\dfrac{7}{2}\)
d. \(\dfrac{1+x}{2x}=\dfrac{5x}{2x}\Leftrightarrow-4x=-1\Leftrightarrow x=\dfrac{1}{4}\)
e. \(\dfrac{-4\left(2x-5\right)}{6\left(2x-5\right)}-\dfrac{2}{6\left(2x-5\right)}=\dfrac{9\left(2x-5\right)}{6\left(2x-5\right)}\)
\(\Leftrightarrow-8x+20-2=18x-45\)
\(\Leftrightarrow-26x=-63\Leftrightarrow x=\dfrac{63}{26}\)
a) 2x + 1 = 3
2x = 2
x = 1
b) ( 2x - 5 ) + 17 = 6
( 2x - 5 ) = 6 - 17
( 2x - 5 ) = -11
2x = -11 + 5
2x = -6
x = -3
c) 10 - 2 x ( 4 - 3x ) = -4
2 x ( 4 - 3x ) = 14
4 - 3x = 7
3x = -3
x = -1
a) 2x + 1 = 3
2x = 3-1
2x=2
x=2:2
x=1