4. Find the roots of x2-4x-12=0 a. X=6 x=-2 C. x=6 x=2 b. X=-6 x=2 d. x=-6 x=-2 5. Find the roots of x2+8x-9=0 a. X=-9 x=1 C. x=-9 x=-1 b. X=9 x=-1 d. x=9 x=1 6. In the quadratic formula x=frac -b ± square root of b2-4ac2a , what is the discriminant? a.2a c. b2-4ac b.4ac d. -b 7. What is the nature of roots if the discriminant is equal to zero 0? a. The roots are real, rational , and unequal b. The roots are real, irrational, and not equal c. There are no real roots