Question

x^2+4x-5=0

Answer 1

\(2x^2+5x+3=0\)

=>\(2x^2+2x+3x+3=0\)

=>2x(x+1)+3(x+1)=0

=>(x+1)(2x+3)=0

=>\(\left[{}\begin{matrix}x+1=0\\2x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-\dfrac{3}{2}\end{matrix}\right.\)

Answer 2

`2x^2+5x+3=0`

`<=>2x^2+2x+3x+3=0`

`<=>2x(x+1)+3(x+1)=0`

`<=>(x+1)(2x+3)=0` 

TH1: `x+1=0<=>x=-1`

TH2: `2x+3=0<=>2x=-3<=>x=-3/2`