Question

Giải phương trình. Em cần gấp ạ

a)\(\sqrt{2x+1}\)=4

b)\(\sqrt{2-3x}\)=5

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

d)\(\sqrt{9x^2}+6x+1\)= x-1

Answer 1

a) PT <=> 2x + 1 = 16 <=> x = \(\frac{15}{2}\)

b) PT <=> 2 - 3x = 25 <=> x = \(\frac{-23}{3}\)

c) PT <=> x² + 2x +1 = 16 <=> \(\left[{}\begin{matrix}x=3\\x=-5\end{matrix}\right.\)

d) PT <=> \(\sqrt{9x^2}\) = -5x -2

ĐK: -5x - 2 ≥ 0 <=> x ≤ \(\frac{-2}{5}\)

PT <=> 9x² = 25x² +20x + 4

<=> \(\left[{}\begin{matrix}x=\frac{-1}{4}\left(KTM\right)\\x=-1\left(TM\right)\end{matrix}\right.\)