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:
$r(r+2w)-2t(2w+r)=$
$=(r+2w)(r-2t)$

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