(y^2 + 14x6 + 49x^2)
When you do this: ( ) ( ) the y^2 will make the first parts y like this:
(y ) (y )
The other part is 49x^2. The square root of 49x^2 is 7x, so let's try this:
(y 7x) (y 7x)
Everything in the original problem is +'s, so let's try this:
(y + 7x) (y + 7x)
Expanding that gives us:
y^2 + 14x + 49x^2
So the factors of y^2 + 14x + 49x^2 are (y+7x) (y + 7x) or just (y + 7x)^2