Question

Which value of b would make x²+bx-30 factorable? A. -31 B. -17 C. 11 D. 13

Answer 1

I think the answer is. D 14

Answer 2

Answer:

D. 13

Step-by-step explanation:

well since it's a quadratic equation, it can be written in the form of ax²+bx+c=0. So we have a=1, b=b and c= -30. Also the roots are given by the equation-

x= -b±$\sqrt{b^{2}-4ac}$ /2a. So all I did was put the number from the choices which would satisfy the sqrt part and that turned out to be 13 since $\sqrt{13^{2}-4*1*(-30)$ = $\sqrt{289}$ = 17. So b=13.