Answer:
(5x +0.7y^2)(5x -0.7y^2) = 25x^2 -0.49y^4
Explanation:
We know the product of a sum and difference can be the difference of squares. The term on the far right is a perfect square: -(0.7y^2)^2.
The binomials on the left look like a sum and difference, so we can fill this in as ...
(5x +0.7y^2)(5x -0.7y^2) = 25x^2 -0.49y^4