Question

If y = ax2 + bx + c represents a parabola with vertex A as shown in the figure and b2 = 2(b + 2ac), where a ≠ 0 and AP = 3, then OP equals (O is origin)

(A) 3

(B) 6

(C) 3/4

(D) 3/2

Answer 1

Correct Answer is: (A) 3

b2 = 2b + 4ac ⇒ 4 ac – b2 = –2b

⇒ AP = OP = 3