Solve for a
a = \frac{15}{2} = 7\frac{1}{2} = 7.5
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30=4a
Subtract 20 from 50 to get 30.
4a=30
Swap sides so that all variable terms are on the left hand side.
a=\frac{30}{4}
Divide both sides by 4.
a=\frac{15}{2}
Reduce the fraction \frac{30}{4} to lowest terms by extracting and canceling out 2.
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