Question

Factor rs - 5s + 5r - 25 by grouping

Answer 1

(s+5)(r-5)

Explanation:

From the first 2 terms, we can factor s to get

rs - 5s = s(r-5).

Similarly, we can factor 5 form the last 2 terms to get

5r - 25 = 5(r-5).

The original expression then becomes

s(r-5) + 5(r-5).

From here, we can treat (r-5) as a single term and factor the rest to get

(s+5)(r-5),

and we are done.