Solve for a
a=12
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2a-3=21
Multiply both sides of the equation by 3.
2a=21+3
Add 3 to both sides.
2a=24
Add 21 and 3 to get 24.
a=\frac{24}{2}
Divide both sides by 2.
a=12
Divide 24 by 2 to get 12.
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