I think you can solve it by
=(x^2 - y^2) *( x^2 + y^2)
= (x -y)*(x+y)*(x^2 + y^2)
Ok -7-7=-14 because your subtracting a negative with a negative and then it will be a negative then if you multiply a negative and a negative it will be a positive
Answer:
We conclude that the line joining the mid-point of two sides of a triangle is equal to half the length of the third side. The converse of this theorem states: If a line is drawn through the mid-point of a side of a triangle parallel to the second side, it will bisect the third side.
Hope this helped you! :)