How do you find the product of $(7u+6v)(7u-6v)$ ?

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Answer 1 · 2016-09-03T02:30:07

$49u^2-36v^2$

In this kind of question, the "middle terms" cancel out, so the first term and final terms multiply:

$(7u+6v)(7u-6v)$

$7uxx7u=49u^2$
$7uxx-6v=-42uv$
$6vxx7u=42uv$
$6vxx-6v=-36v^2$

The middle terms cancel and we're left with:

$49u^2-36v^2$

How do you find the product of (7u+6v)(7u-6v)(7u+6v)(7u-6v)?