2)
6x+3.8=20.6
6x=20.6-3.8
6x=16.8
x=2.8
_____________
6.7y+13+3.1y=86.5
6.7y+3.1y=86.5-13
9.8y=73.5
y=7.5
______________
(15b+b)/4=3
16b/4=3
4b=3
b=4/3=1 1/3
______________
12 3/17+x+8 16/17=23 2/17
x=23 2/17-12 3/17-8 16/17
x=393/17-207/17-152/17
x=34/17
x=2