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a) \(x-7=4x+10\)
\(x-4x=10+7\)
\(-3x=17\)
\(x=\dfrac{17}{-3}\)
Vậy \(x=\dfrac{17}{-3}\)
b) \(2x+5=-3x+7\)
\(2x+3x=7-5\)
\(5x=2\)
\(x=\dfrac{2}{5}\)
Vậy \(x=\dfrac{2}{5}\)
c) \(x-\left(3x+7\right)=6x-1\)
\(x-3x-7=6x-1\)
\(-2x-7=6x+1\)
\(-7-1=6x+2x\)
\(-8=8x\)
\(x=\dfrac{-8}{8}=-1\)
Vậy \(x=-1\)
d) \(x+\left(5x-1\right)=15\)
\(x+5x-1=15\)
\(6x=15+1\)
\(6x=16\)
\(x=\dfrac{16}{6}=\dfrac{8}{3}\)
Vậy \(x=\dfrac{8}{3}\)
1 , x - 7 = 4x + 10
x - 4x = 10 + 7
- 3x = 17
x = 17 : ( - 3 )
x = \(\dfrac{-17}{3}\)
2 , 2x + 5 = -3x + 7
2x + 3x = 7 -5
5x = 2
x = 2 : 5
x =\(\dfrac{2}{5}\)
3 , x - ( 3x + 7 ) = 6x - 1
x - 3x - 7 = 6x - 1
x - 3x -6x = -1 +7
-8x = 6
x = 6 : ( -8 )
x = \(\dfrac{-3}{4}\)
4 , x + ( 5x -1 ) = 15
x + 5x - 1 = 15
x + 5x = 15 + 1
6x = 16
x = 16 : 6
x = \(\dfrac{8}{3}\)
5 , / x + 1 / = / 2x - 5 /
TH 1 : x + 1 = 2x - 5
x - 2x = -5 -1
- x = -4
= > x = 4
TH 2 : -x -1 = -2x + 5
-x + 2x = 5 + 1
x = 6
6 , / 3x + 8 / - / x -10 / = 0
3x + 8 - x + 10 = 0
3x - x = 0 - 10 - 8
2 x = -18
x = -18 : 2
x = - 9
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Tham khảo tại đó đi ~
#)Giải :
Có \(3x=2y=5z\)
\(\Leftrightarrow\frac{x}{2}=\frac{y}{3};\frac{y}{5}=\frac{z}{2}\)
\(\Leftrightarrow\frac{x}{10}=\frac{y}{15}=\frac{z}{6}\)
Áp dụng tính chất dãy tỉ số bằng nhau, ta có :
\(\frac{x}{10}=\frac{y}{15}=\frac{z}{6}=\frac{2x}{20}=\frac{y-2x}{15-20}=\frac{5}{-5}=-1\)
\(\Rightarrow\hept{\begin{cases}\frac{x}{10}=-1\\\frac{y}{15}=-1\\\frac{z}{6}=-1\end{cases}\Leftrightarrow\hept{\begin{cases}x=-1.10\\y=-1.15\\z=-1.6\end{cases}\Leftrightarrow}\hept{\begin{cases}x=-10\\y=-15\\z=-6\end{cases}}}\)
Vậy .......................................................................................
a) Ta có : |2x - 5| = x + 1
\(\Leftrightarrow\orbr{\begin{cases}2x-5=-x-1\\2x-5=x+1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x+x=-1+5\\2x-x=1+5\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}3x=4\\x=6\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{4}{3}\\x=6\end{cases}}\)
a)2x-1=3x+5
⇔ 2x -3x = 5 +1
⇔ -x = 6
⇔ x = -6
Vậy x= -6
b)2(x-3)+1=3(1-x)+2
⇔ 2x -6 +1 = 3 -3x +2
⇔ 2x - 5 = 5 -3x
⇔ 2x +3x = 5 +5
⇔ 5x = 10
⇔ x = 2
Vậy x= 2
\(a,2x\left(4x^2-5\right)\)
\(=8x^3-10x\)
\(b,3x^2\left(2y-1\right)-\left[2x^2\left(5y-3\right)-2x\left(3x^2+1\right)\right]\)
\(=6x^2y-3x^2-\left[10x^2y-6x^2-6x^3-2x\right]\)
\(=6x^2y-3x^2-10x^2y+6x^2+6x^3+2x\)
\(=-\left(10x^2y-6x^2y\right)+\left(6x^2-3x^2\right)+6x^3+2x\)
\(=-4x^2y+3x^2+6x^3+2x\)
* Trả lời:
\(\left(1\right)\) \(-3\left(1-2x\right)-4\left(1+3x\right)=-5x+5\)
\(\Leftrightarrow-3+6x-4-12x=-5x+5\)
\(\Leftrightarrow6x-12x+5x=3+4+5\)
\(\Leftrightarrow x=12\)
\(\left(2\right)\) \(3\left(2x-5\right)-6\left(1-4x\right)=-3x+7\)
\(\Leftrightarrow6x-15-6+24x=-3x+7\)
\(\Leftrightarrow6x+24x+3x=15+6+7\)
\(\Leftrightarrow33x=28\)
\(\Leftrightarrow x=\dfrac{28}{33}\)
\(\left(3\right)\) \(\left(1-3x\right)-2\left(3x-6\right)=-4x-5\)
\(\Leftrightarrow1-3x-6x+12=-4x-5\)
\(\Leftrightarrow-3x-6x+4x=-1-12-5\)
\(\Leftrightarrow-5x=-18\)
\(\Leftrightarrow x=\dfrac{18}{5}\)
\(\left(4\right)\) \(x\left(4x-3\right)-2x\left(2x-1\right)=5x-7\)
\(\Leftrightarrow4x^2-3x-4x^2+2x=5x-7\)
\(\Leftrightarrow-x-5x=-7\)
\(\Leftrightarrow-6x=-7\)
\(\Leftrightarrow x=\dfrac{7}{6}\)
\(\left(5\right)\) \(3x\left(2x-1\right)-6x\left(x+2\right)=-3x+4\)
\(\Leftrightarrow6x^2-3x-6x^2-12x=-3x+4\)
\(\Leftrightarrow-15x+3x=4\)
\(\Leftrightarrow-12x=4\)
\(\Leftrightarrow x=-\dfrac{1}{3}\)
\(\frac{4}{5}-2x=\frac{2}{5}+3x\)
\(\frac{4}{5}-\frac{2}{5}=2x+3x\)
\(\frac{2}{5}=5x\)
\(x=\frac{2}{25}\)
Ta có :\(\frac{4}{5}-2x=\frac{2}{5}+3x\)
\(\Leftrightarrow\) \(\frac{4}{5}-\frac{2}{5}=3.x+2.x\)
\(\Leftrightarrow\)\(\frac{2}{5}=5.x\)
\(\Leftrightarrow x=\frac{2}{5}:5\)
\(\Leftrightarrow x=\frac{2}{25}\)
~~~ AI NGANG QUA CHO CHÁU XIN 1 L~I~K~E~~~