Question

Find all the zeros of the quadratic function:
y=x^2+15x+36

Answer 1

x=-12 and -3

Explanation:

The quadratic formula is

`x=(-b+√(b^2-4ac) )/(2a)`.

It is important because while some quadratics are factorable and can be solved not all are. The formula will solve all quadratic equations and can also give both real and imaginary solutions. We will substitute a=1, b=15 and c=36.

`x=(-b+/-√(b^2-4ac) )/(2a)\\x=(-15+/-√((15)^2-4(1)(36)) )/(2(1))\\x=(-15+/-√(225-144) )/(2)`

We will now simplify and solve.

`x=(-15+/-√(81))/(2)\\x=(-15+/-9)/(2)`

x=-12 and x=-3