Answer
$625a^4-50a^2+1$
Work Step by Step
RECALL:
$x^my^m=(xy)^m$
Use the rule above to obtain:
$=[(5a+1)(5a-1)]^2$
Multiply the two binomials using the formula $(a+b)(a-b)=a^2-b^2$ to obtain:
$=[(5a)^2-1^2]^2
\\=(25a^2-1)^2$
Use the formula $(a-b)^2=a^2-2ab+b^2$ with $a=25a^2$ and $b=1$ to obtain:
$=(25a^2)^2-2(25a^2)(1)+1^2
\\=625a^4-50a^2+1$
