Question

If x²+4x+3=0,2x²+3ax-9=0 have a common root find value of a and common x​

Answer 1

Answer:

Correct option is

A

±3

Let the common root of the equations be p.

Then, p

2

+4ap+3=0 ⇒ 2p

2

+8ap+6=0

and 2p

2

+3ap−9=0

Equating both the equations

2p

2

+8ap+6 = 2p

2

+3ap−9

⇒ 5ap=−15

⇒ ap=−3

Substitute the value of ap in the first equation

Then, p

2

+4(−3)+3=0

⇒ p

2

=9

⇒ p=±3

⇒ a=±1

∴ Option B is correct.