Question

Giải các PT:

a) \(\sqrt{9-12x+4x^2}=4\)

b) \(\sqrt{3x^2-18x+28}+\sqrt{4x^2-24x+25}=-5-x^2+6x\)

Answer 1

a,

\(\sqrt{9-12x+4x^2}=4\\ \sqrt{\left(3-2x\right)^2}=4\\ \left|3-2x\right|=4\\ \Rightarrow\left[{}\begin{matrix}3-2x=4\\3-2x=-4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}2x=-1\\2x=7\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{-1}{2}\\x=\dfrac{7}{2}\end{matrix}\right.\)

Vậy \(\left[{}\begin{matrix}x=\dfrac{-1}{2}\\x=\dfrac{7}{2}\end{matrix}\right.\)

Answer 2

b) Đề có sai ko vậy?