How do you multiply #(7+2a)(7-2a)#?

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Answer 1 · 2017-01-18T16:16:17

See the entire multiplication process below:

To multiply these two terms you multiply each individual term in the left parenthesis by each individual term in the right parenthesis.

#(color(red)(7) + color(red)(2a))(color(blue)(7) - color(blue)(2a))# becomes:

#(color(red)(7) xx color(blue)(7)) - (color(red)(7) xx color(blue)(2a)) + (color(red)(2a) xx color(blue)(7)) - (color(red)(2a) xx color(blue)(2a))#

#49 - 14a + 14a - 4a^2#

We can now combine like terms:

#49 + (-14 + 14)a - 4a^2#

#49 + 0 - 4a^2#

#49 - 4a^2#

#-4a^2 + 49#