Question

giải pt

1)x/√2x+3=11/5

2)√y+1 =-2/5

Answer 1

1: ĐKXĐ: \(x>-\dfrac{3}{2}\)

\(\dfrac{x}{\sqrt{2x+3}}=\dfrac{11}{5}\)

=>\(5x=11\sqrt{2x+3}\)

=>\(\left\{{}\begin{matrix}x>0\\25x^2=121\left(2x+3\right)\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}x>0\\25x^2-242x-363=0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}x>0\\25x^2-275x+33x-363=0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}x>0\\\left(x-11\right)\left(25x+33\right)=0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}x>0\\\left[{}\begin{matrix}x=11\\x=-\dfrac{33}{25}\end{matrix}\right.\end{matrix}\right.\)

=>x=11

2: ĐKXĐ: y>=-1

\(\sqrt{y+1}=-\dfrac{2}{5}\)

mà \(\sqrt{y+1}>=0\forall y>=-1\)

nên \(y\in\varnothing\)