Question

If the quadratic equations, ax² + 2cx + b = 0 and ax² + 2bx + c = 0 (b ≠ c) have a common root, then a + 4b + 4c is equal to :

(A) - 2

(B) - 2

(C) 0 

(D) 1

Answer 1

Correct option (C) 0

Explanation:

ax² + 2cx + b = 0 and ax² + 2bx + c = 0 ................ (2)

Subtracting 2(c–b) x = (c–b) 

x = 1/2 is a common root 

Put in equation a/4 + 2c/2 + b = 0 

⇒ a + 4c + 4b = 0