Explanation:
26-4s=9s
26=9s+4s
26=13s
s=26/13
s=2
-3r+10=15r-8
-3r-15r=-8-10
-18r=-18
r=-18/-18
r=1
-9(t-2)=4(t-15)
-9t+18=4t-60
-9t-4t=-60-18
-13t=-78
t=-78/-13
t=6
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