How do you factor by grouping, #r^2-4tw +2wr - 2tr#?

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Answer 1 · 2015-04-21T12:49:00

Collect #r# frm the first and third term and #-2t# from the second and fourth:
#r(r+2w)-2t(2w+r)=#
#=(r+2w)(r-2t)#