edit: my bad it was 20 not 23!

It starts getting into fractions and I'm just having a really tough time I have no idea what I'm doing wrong... I can usually do the ones without fractions but with just makes it so much harder. I've been doing this question for like 2 hours (srs). One time I got everything to work out right except the 2nd equation because of negatives (answers didn't have fractions like they do now) so I had to re-do it and haven't come close since.

a + b + c = 20

2a + b -2c = -53

3a - 4b + c = 59

can anyone help me out and show me how to do it? I always do substitution but if elimination is easier im open to that to thanks