Question

Q.8 If 2 is a root of the equation x`2 + ax + 12 = 0 and the quadratic equation
x`2 + ax +q = 0 has equal roots, then q =
la) 12 (b) 8 (c) 20 (d) 16​

Answer 1

Answer:d)16

Step-by-step explanation:

Given 2 is a root of the equation x^2+ax+12.

So put 2 in place of x

>2^2+2a+12=0. (As it is a root of the eqn.)

>2a= -12-4

=-16

>a= -8

Now the second equation becomes

x^2 -8x +q=0

Now 2 roots are equal.So

as sum of two roots is -(-8)/1. (-b/a)

=8

Therefore each root is 8/2=4

Put it in place of x in second equation.

4^2-8*4 +q=0

q=32- 16

= 16

So answer is d) 16