*Remember : Roots of a quadratic equation are the values of variables/unknowns that satisfy the equation.*

__Example__

(a)Given x=3 is the root of the quadratic equation ${x}^{2}+2x+p=0$ , find the value of p.

(b) The roots of the quadratic equation $3{x}^{2}+hx+k=0$ are -2 and 4. Find the value of h and k.