Question

determine the real roots (5x²+20)(3x²-48)

Answer 1

Do you have an idea about discriminants?

Answer 2

5x²+20 = 0 or 3x²-48 = 0

Answer 3

But 5x² = -20 has complex roots
3x² = 48 implies x² = 16 which has real roots of +4 and -4

Answer 4

we're supposed to use the factor theorem