Explanation: This is a quadratic equation, so the easiest way to solve this is by splitting up the middle term. What are two numbers that when multiplied gives -40, and adds to give 3? (8, -5)
You can then split up the middle term like so: x² + 8x - 5x - 40 = 0
and factorise x² + 8x and -5x -40. x(x + 8) -5(x + 8) and group together like terms: [tex](x - 5)(x + 8)[/tex]