Answer
$(5y-1)^2$
Work Step by Step
RECALL:
A perfect square trinomial can be factored using either of the following formulas:
(i) $a^2+2ab+b^2= (a+b)^2$
(ii) $a^2-2ab+b^2=(a-b)^2$
The given perfect square trinomial can be written as:
$=(5y)^2-2(5y)(1) + 1^2$
This trinomial has the same form as the perfect square trinomial in formula (ii) above.
Factor using formula (ii) with $a=5y$ and $b=1$ to obtain:
$=(5y-1)^2$
