Question

simplify the following expression.
$(5x - 9)(5x + 9)$
$?x^{2}-$

Explanation:

Step1: Apply difference of squares rule

Recall that $(a-b)(a+b)=a^2-b^2$. Here, $a=5x$, $b=9$.

Step2: Calculate $a^2$

$a^2=(5x)^2=25x^2$

Step3: Calculate $b^2$

$b^2=9^2=81$

Step4: Substitute into the formula

$(5x-9)(5x+9)=25x^2-81$

Answer:

The first blank is 25, the second blank is 81, so the simplified expression is $25x^2 - 81$