Question

tìm x biết :

a) (2x-1)^2-(x+2)^2=0

b) (4x-3)^2=(1-2x)^2

Answer 1

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

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

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

\(\Rightarrow3x+1=0\) hoặc \(x-3=0\)

\(\Rightarrow x=-\frac{1}{3}\) hoặc \(x=3\)

b) \(\left(4x-3\right)^2=\left(1-2x\right)^2\)

\(\Rightarrow\left(4x-3\right)^2-\left(1-2x\right)^2=0\)

\(\Rightarrow\left(4x-3+1-2x\right)\left(4x-3-1+2x\right)=0\)

\(\Rightarrow\left(2x-2\right)\left(6x-4\right)=0\)

\(\Rightarrow2x-2=0\) hoặc  \(6x-4=0\)

\(\Rightarrow x=1\) hoặc \(x=\frac{4}{6}\)