Answer :
I believe your initial equation f(x)=x^2x-35 , should be: f(x)=x²+2x-35
If so, then the x intercepts are the root of this quadratic equation that is
x' =5 & x" = -7 (A)
If so, then the x intercepts are the root of this quadratic equation that is
x' =5 & x" = -7 (A)