Question 1058804
(x+3)(x+5) are factors
a(x^2+8x+15)=0
When x=7
a(49+56+15)=-720
a(120)=-720
a=-6
f(x)=-6x^2-48x-90
{{{graph(300,300,-10,10,-800,10,-6x^2-48x-90)}}}
{{{graph(300,300,-10,10,-10,10,-6x^2-48x-90)}}}