Question 74119
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Please show me how to factoring by grouping. Thanks!

r^2-9tw+3rw-3rt ?

   (r^2 + 3rw) + (-3rt - 9tw)

  r(r + 3w) + (-3t)(r + 3w)     notice there is a common factor

  (r - 3t)(r + 3w)