Y=12
ST=60
TU=30
Step-by-step explanation:
5y+2y+6=90
subtract 6 from 90
and add 5y and 2y
7y=84
then divide 84 by 7
and what ever you do to one side y ok u have to do to the other so the 7 cancels itself out
y=12
then plug it back in
5×12=60
2×12+6=30
30+60=90
