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Example
3(r+2s)=2t-4
a⋅(b-2)=3b
3(r+2s)=2t-4
a⋅(b-2)=3b
Question
$$(x-9)(x+9)$$
Evaluate
$x^{2}-81$
Solution Steps
Multiplication can be transformed into difference of squares using the rule: $\left(a-b\right)\left(a+b\right)=a^{2}-b^{2}$.
$$x^{2}-9^{2}$$
Calculate $9$ to the power of $2$ and get $81$.
$$x^{2}-81$$
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Expand
$x^{2}-81$
Solution Steps
Multiplication can be transformed into difference of squares using the rule: $\left(a-b\right)\left(a+b\right)=a^{2}-b^{2}$.
$$x^{2}-9^{2}$$
Calculate $9$ to the power of $2$ and get $81$.
$$x^{2}-81$$
Show Solution
Hide Solution
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