To solve for y, you need to separate it in one side and the other terms in the other side..... as follows:
a(n+y)=10y+32a
an + ay = 10y + 32a
an - an + ay = 10y + 32a - an
ay = 10y + 32a - an
ay -10y = 32a - an
y (a-10) = (32 - n)a
y = {a(32-n)} / (a-10)
