Question

If the equation \(x^2+ax+b=0\) & \(x^2+bx+a=0\) have common root then the numerical value of a+b is

Answer 1

x^2 + ax + b = x^2 + bx + a

ax - bx + b - a = 0

a(x - 1) - b(x - 1) = 0

(a - b)(x - 1) = 0

a - b = 0

therefore a = b

Root: x=1

Now sub'ing back:

1 + a + b = 0

a + b = -1

Answer 2

Wow Thankyou =D

Answer 3

Not sure if this is correct. But I hope it helps

Answer 4

Why x=1?

Answer 5

(a - b)(x - 1) = 0

Therefore x must be equal to 1 to satisfy the equation.

Answer 6

Btw answer is Right :) i have the final answer =D

Answer 7

Ohhhh yeahhhh !!!

Answer 8

haha, cool :) Glad I could help!

Answer 9

=)