How do you multiply #(3a-7b)^2#?

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1 Answer
smendyka
Jan 18, 2017

See the entire multiplication process below:

Explanation:

This problem can be rewritten as:

#(color(red)(3a) - color(red)(7b))(color(blue)(3a) - color(blue)(7b))#

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

#(color(red)(3a) - color(red)(7b))(color(blue)(3a) - color(blue)(7b))# becomes:

#(color(red)(3a) xx color(blue)(3a)) - (color(red)(3a) xx color(blue)(7b)) - (color(red)(7b) xx color(blue)(3a)) + (color(red)(7b) xx color(blue)(7b))#

#9a^2 - 21ab - 21ab + 49b^2#

We can now combine like terms:

#9a^2 + (-21 - 21)ab + 49b^2#

#9a^2 - 42ab + 49b^2#

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