Question

Tim Nghiem 5x² 4x-9

Answer 1

\(5x^2+4x-9=0\)

\(\Leftrightarrow5x^2+9x-5x-9=0\)

=>(5x+9)(x-1)=0

=>x=1 hoặc x=-9/5

Answer 2

\(5x^2??4x\)

Answer 3

`5x^2 +4x -9 =0`

`<=> 5x^2 +9x -5x -9=0`

`<=> 5x^2 -5x + 9x-9=0`

`<=> 5x(x-1)+9(x-1)=0`

`<=> (5x+9)(x-1)=0`

`<=>`\(\left[{}\begin{matrix}5x=-9\\x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{9}{5}\\x=1\end{matrix}\right.\)