Use Euclid's algorithm to find a multiplicative inverse of 15 mod 88, hence solve the linear congruence 15x=20(mod 88)

Question

So far I have:
88=5x15+13
15=1x13+2
Backwards substitution gives
15v+18w=1
1=15-1x13
=15-1(88-5x15)
=15x15-1x88

now very stuck what to do from here:(