Question 988266
quadratic equation whose roots are :
{{{x[1]=9}}} and {{{x[2]=-5 }}}

use zero product theorem:

{{{y=(x-x[1])(x-x[2])}}}

{{{y=(x-9)(x-(-5))}}}

{{{y=(x-9)(x+5)}}}

{{{y=x^2+5x-9x-45}}}

{{{highlight(y=x^2-4x-45)}}}=>your equation


{{{drawing( 600, 600, -15, 15, -50, 15,
locate(9,1.7,p(9,0)),locate(-5,1.7,p(-5,0)),
circle(9,0,.2),circle(-5,0,.2),
 graph( 600, 600, -15, 15, -50, 15, x^2-4x-45)) }}}