The number of values of the pair (a,b) for which a(x+1)^2+b(x^2-3x-2)+x+1=0 is an identity in x is

JEE Advanced Mathematics question

The number of values of the pair for which

a(x++-3x-2)+x+1=0

is an identity in is

Answer: (A)

Expanding: for all requires

a+b=0, 2a-3b+1=0, a-2b+1=0.

From the first, ; then the second gives

Create a free account to read the complete working (3 steps), and practise questions like this in a timed test.

Question ID VK-107893