Did I do this right? Find values of q if x^2+4x+q-2=0 has two different real roots

Question

0

615

1

Find values of q if x^2+4x+q-2=0 has two different real roots

Did I do this right?

x^2+4x+9-2=0

4^2-4(q-2)=0

16-4q+8=0

-4q+24=0

-4q=-24

q=6

My teacher crossed out my answer even though they gave me full credit for it? I don't know if it's correct or not.

Guest Sep 28, 2016

Alan · Answer 1 · 2016-09-28T07:15:21

You have found the value of q that gives two equal roots!

For two different real roots your second line should be: 4^2-4(q-2) > 0

This will result in a range of possible q values (q<6 rather than q = 6).