If x = 1 is a common root of ax 2 + ax + 2 = 0 and x 2 + x + b = 0 then, ab =

Question

Philoid · Accepted Answer

Since x = 1 is root of equation

Then it satisfy the equation

Putting x = 1 in first equation

a + a + 2 = 0

2a + 2 = 0

a = – 1

Putting x = 1 in equation second

1 + 1 + b = 0

2 + b = 0

b = – 2

ab = – 1 x – 2

ab = 2