Answer:
a=15
Step-by-step explanation:
3a+b = 54
Let b=9
3a+9 = 54
Subtract 9 from each side
3a+9-9= 54-9
3a = 45
Divide each side by 3
3a/3 = 45/3
a = 15
Answer:
[tex]3a+b=54[/tex]
[tex]3a+9=54\:[b=9][/tex]
[tex]3a=54-9[/tex]
Subtract 9 from both sides
[tex]3a=45[/tex]
Divide both sides by 3
[tex]\frac{3a}{3}=\frac{45}{3}[/tex]
[tex]a=15[/tex]
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