Question

If one zero of quadratic polynomials $x^2-x-\left(2+2k\right)is-4$. find the value of $K$.

Answer 1

$f\left(x\right)=x^2-x-(2+2k)$

one zero is $-4$

$\Rightarrow$ $f(-4)=0$

$\Rightarrow$ ${(-4)}^2-(-4)-(2+2k)=0$

$\Rightarrow$ $16+4=2+2k$

$\Rightarrow$ $18=2k$

$\Rightarrow$ $k=9$