Find the constant k such that the quadratic 2x^2 + 3x + 8x - x^2 + 4x + k has a double root.
First, let's combine all our like terms. We have
\(x^2+15x+k\)
There are many possibilities for what k may be.
As long as two factors of k add up to 15, we are good.
Examples are such as
\(k=14; x^2+15x+14 = (x+14)(x+1)\\ k=56; x^2+15x+56=(x+7)(x+8)\)
k can also be negative, such as
\(k=-100; x^2+15x-100 = (x+20)(x-5)\)
Thanks! :)