10x^2y - 15xy^2?
Completely factor

By factoring our 5 you get, 5(2x^2y-3xy^2)

Adiamond or any shape with 4 sides has angles that always add up to 360 degrees. 1 right angle is 90 degrees so 90 times 3 is 270. so far we currently have 270 degrees. now we do 360-270 and we find out that the missing angle is 90 degrees. a diamond is basically a rotated square. the answer is b.