Question

Factorise:
40 + 3x – x²

Answer 1

$$\begin{gathered} -x^2+3x+40 \\ =-x^2+8x-5x+40 \\ =-x\left(x-8\right)-5\left(x-8\right) \\ =\left(x-8\right)\left(-x-5\right) \\ =\left(8-x\right)\left(x+5\right) \end{gathered}$$