Question

a)\(\sqrt{3x-1}=2\)   c) \(\sqrt{x^2-4x+4}=3x-1\)

b)\(\sqrt{x+}=2-x\)   d)\(\sqrt{x^2+4}=\sqrt{3x+8}\)

Answer 1

a)\(\sqrt{3x-1}\)\(=2\)

⇔\(\text{3x-1=2}^2\)

⇔\(3x=5\)

⇔\(x=\dfrac{5}{3}\)

b)\(\sqrt{x^2-4x+4}\)\(\text{=3x-1}\)

⇔\(\text{x-2=3x-1}\)

⇔\(-2x=1\)

⇔\(x=\)\(\dfrac{-1}{2}\)

c)\(\sqrt{x}\)=2-x sai đề bài

d)\(\sqrt{x^2+4}\)=\(\sqrt{3x+8}\)

⇔\(x^2\)\(\text{+4=3x+8}\)

⇔\(x^2\)\(-3x-4=0\)

⇔\(\left(x+1\right)\left(x-4\right)=0\)

⇔\(\left[{}\begin{matrix}x=4\\x=-1\end{matrix}\right.\)