Elimination method or substitution method.
1. 3/5x = 1/2y + 11
2. 3x + 8y + 13
well, first lets get rid of those nasty fractions ...
multiply the first by 10
6x = 5y + 110
or
6x - 5y = 110 **
3x + 8y = 13 <--- I assume yours was a typo
double the 2nd:
6x + 16y = 26 ***
subtract *** from **
-21y = 84
y = -4
sub back into 3x+8y=13 to find x