PIMSO 2022 - Mathematics - Grade 10 / Secondary 4 - National Round Question 17

Let R and F ($R,F\ne0$) be the roots of the equation $x^2-3x-m=0$. If RF and R+F are the roots of the equation $(c+1)x^2-sx+m=0$ and $c+1+s+m=0$, then find the value of $c+s-m$.