Question

What are the roots of the function y = 4x2 + 2x – 30? To find the roots of the function, set y = 0. The equation is 0 = 4x2 + 2x – 30.
Factor out the GCF of .
Next, factor the trinomial completely. The equation becomes .
Use the zero product property and set each factor equal to zero and solve. The roots of the function are .

Answer 1

4x² + 2x - 30 = 0

factor out the GCF:
2(2x² + x - 15) = 0

factor the trinomial completely:
2x² + x - 15 = 0
2x² + 6x - 5x - 15 = 0
2x(x + 3) - 5(x + 3) = 0
(2x - 5)(x + 3) = 0

use the zero product property and set each factor equal to zero and solve:
2x - 5 = 0     or     x + 3 = 0
2x = 5                   x = -3
x = 2.5

The roots of the function are x=-3,  x=2.5

Answer 2

Factor out the GCF of "2."  Next factor the trinomial completely. The equation becomes "0=2(2x-5)(x+3)." Use the zero product property and set each factor equal to zero and solve. The roots of the function are "-3 and 5/2."

Hope this helps!

-Charlie