Roots of the polynomial are values of x when f(x)=0,so
to find the roots of the polynomial we need to solve the equation
x²+9x-70=0 , a=1, b=9,c=-70
[tex]x= \frac{-b+/- \sqrt{ b^{2}-4ac } }{2a}
[/tex]
[tex]x= \frac{-9+/- \sqrt{81+4*1*70} }{2} = \frac{-9+/- \sqrt{361} }{2}= \frac{-9+/-19}{2}
x_{1}=5, x_{2}=-14
[/tex]
