How do you FOIL #(3x-4)(3x+4)#?

1 Answer
Jun 22, 2016

#(3x-4)(3x+4)=color(green)(9x^2-16)#
(see below for use of FOIL method)

Explanation:

Given #(3x-4)(3x+4)#

FOIL:
#{: ("First terms:",,3x xx 3x,"=",9x^2), ("Outside terms:",,3x xx 4,"=",12x), ("Inside terms:",,-4 xx 3x,"=",-12x), ("Last terms:",,-4xx4,"=",-16), (,,"Sum","=",9x^2-16) :}#