Well what i did was subtract 10 from 15 it get 5 for one side length and the other would be 24-16= 8. the scale factor would be +5 and + 8.
Hope this helped :)
Check the image below for working
"Product" signifies multiplication, and "half" means divide by two (or multiply by 1/2). So half the product of b and c is (bc)/2 or (1/2)(bc).
Please note that you have to use the reason vert. opp. angles to find x, hope it helps:)