SOLUTION: Find k if the following equations have a double root: kx^2+4x+3=0 I know that this simplifies to (x+1)(x+3). but I don't know what I am supposed to do from there to find k.

Algebra ->  Expressions-with-variables -> SOLUTION: Find k if the following equations have a double root: kx^2+4x+3=0 I know that this simplifies to (x+1)(x+3). but I don't know what I am supposed to do from there to find k.       Log On


   

Question 1138925: Find k if the following equations have a double root:
kx^2+4x+3=0
I know that this simplifies to (x+1)(x+3). but I don't know what I am supposed to do from there to find k.
Basically, I need to find the value of k.
Thanks so much!
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Much the same as the other one like this you asked, for "double root", you are looking for discriminant of 0.
4%5E2-4%2Ak%2A3=0
16-12k=0
4-3k=0
highlight%28k=4%2F3%29

Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!

Find k if the following equations have a double root:
kx^2+4x+3=0
I know that this simplifies to (x+1)(x+3). but I don't know what I am supposed to do from there to find k.
Basically, I need to find the value of k.
Thanks so much!
That's NOT CORRECT! The factors ARE NOT (x + 1)(X + 3). 

A DOUBLE-ROOT exists when there is a PERFECT SQUARE TRINOMIAL, and also occurs when the DISCRIMINANT, b2 - 4ac equals 0.