How do you factor by grouping $y^2+7y+3y+21$ ?

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Answer 1 · 2015-04-21T12:36:21

Collect $y$ frm the first and third term and $7$ from the second and fourth:
$y(y+3)+7(y+3)=$
$=(y+3)(y+7)$

How do you factor by grouping y^2+7y+3y+21y^2+7y+3y+21?