How do you factor by grouping: r^2 - 20tw + 4wr - 5tr?

1 Answer
Apr 9, 2015

r^2-20tw+4wr-5tr

Group r^2 and -5tr, and 4wr-20tw.

r^2-5tr+4wr-20tw

Factor out the r from the first group, r^2-5tr.

r(r-5t)+4wr-20tw

Factor out 4w from the second group, 4wr-20tw.

r(r-5t)+4w(r-5t)

Factor out the common term.

(r+4w)(r-5t)