Question

1. fg - 5g + 4f - 20

Explanation:

Step1: Group terms

Group the first two terms and the last two terms: $(fg - 5g)+(4f - 20)$

Step2: Factor out GCF from each group

Factor out $g$ from the first group and $4$ from the second group: $g(f - 5)+4(f - 5)$

Step3: Factor out common binomial factor

Factor out $(f - 5)$ from both terms: $(f - 5)(g + 4)$

Answer:

$(f - 5)(g + 4)$