How do you FOIL # (7-a)^2 #?

1 Answer
May 28, 2015

#(7-a)^2 = color(red)((7-a))*color(blue)((7-a))#

F irst terms: #color(red)(7) xx color(blue)(7) = 49#
O utside terms:# color(red)(7) xx color(blue)((-a)) = (-7a)#
I nside terms: #color(red)((-a)) xx color(blue)(7) = (-7a)#
L ast terms: #color(red)((-a)) xx color(blue)((-a)) = a^2#

Sum of FOIL = #49 -14a+a^2#