Remark
There are occasions where this is very handy to know. Use FOIL.
Solve
F: (First): x*y = xy
O: (Outside): x *(-9) = - 9x
I:(Inside): (-7)*y = - 7y
L:(Last): (-7)*(-9) = 63
Add the terms together
xy - 9x - 7y + 63 <<<< Answer
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