8. Factor.

x2 + x - 20

When we multiply the first and last coefficients, (1)(-20) = -20 so we are looking for a pair of factors of 20 which have a difference of 1. There is such a pair, 4 and 5. This gives us the coefficients of the O and I terms when we recover the FOIL step.

F     O     I     L

x2 - 4x + 5x + 20

This will come form

(x + 5)(x - 4)