Answer:
It isn't
Step-by-step explanation:
An x can't have to y's
way to remember: x=exes y=wives
you can have multiple exes (x's) but only one wife (y's)
0 has two y's
1/2(15)(13+17)
15/2(13+17)
15/2(30)
= 225
I hoe that's help.
30 and 40