Question

If both x+2 and 2x+1 are factors of ax2 +2x+b then the value of a-b is

Answer 1

Step-by-step explanation:

Since both (x - 2) and (2x - 1) are factors of ax2 + 5x + b.

x = 2 or x = 1/2

Therefore, substituting x = 2 in the equation,

4a + 10 + b = 0

Or, 4a + b = -10… (1)

Also, x = 1/2, therefore, substituting x = 1/2 in the equation,

On solving (1) and (2), a = -2 and b = -2

Hence, a - b = -2 - (-2) = -2+2 = 0.