Question 1209248: Find the constant k such that the quadratic 2x^2 + 3x - 20x + 3x^2 + k has a double root. Found 2 solutions by Edwin McCravy, mccravyedwin:Answer by Edwin McCravy(20055) (Show Source):
It will have a double root if its discriminant b2-4ac = 0
<-- answer
Checking:
10x-17=0; 10x-17=0
10x=17; 10x=17
x=; x=
So both roots are the same, so it has a double root if
So is correct.
Edwin
You could also do it this way:
That would have a double root if it would factor this way,
as the sum of the square roots of the first and last terms,
with the same sign between them as the middle term has:
Then the middle term's coefficient would equal -17
Edwin
