-25/36 + y^2

This expression can be rewritten as $$y^2 - 25/36$$. This is a difference of squares, in the form of $$a^2 - b^2 = (a-b)(a+b)$$.

Here, $$a^2 = y^2$$, so $$a = y$$. Also, $$b^2 = 25/36$$, so $$b=5/6$$.

Thus, the factored form is $$(y - 5/6)(y + 5/6)$$.