Question

[Đoàn Hà]

Tìm X biết.

a) 7x - 10 = 5x - 6     
b) 3x( x - 2 ) + x - 2 = 0

c) 2x² + 7x - 4 = 0

Answer 1

[Vương Hải Nam]

a) \(7x-10=5x-6\)

\(7x-5x=-6+10\)

\(2x=4\)

\(x=2\)

b) \(3x\left(x-2\right)+x-2=0\)

\(\left(x-2\right)\left(3x+1\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-2=0\\3x+1=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\x=-\frac{1}{3}\end{cases}}\)

c) \(2x^2+7x-4=0\)

\(2x^2-x+8x-4=0\)

\(x\left(2x-1\right)+2\left(2x-1\right)=0\)

\(\left(2x-1\right)\left(x+2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}2x-1=0\\x+2=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{1}{2}\\x=-2\end{cases}}\)

Answer 2

[trongnghia]

7x-10=5x-6<=>7x-5x=-6+10<=>2x=4=>x=2

3x(x-2)+x-2=0<=>(x-2)(3x+1)=0<=>x-2=0=>x=2    HAY 3x+1=0=>x=-1/3

2x²+7x-4=0.

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