A) 5(x-y)
= 5(3)
=15
B) 2x-2y
=2(x-y)
=2(3)
=6
C)y-x
=3
Explaining
At the top of the question it is written that x-y =3 so in A we place x-y by 3 ad solve the multiplication in B we take 2 common and then place the value of x-y with 3
In C we just put the 3
HOPE THAT HELPS