Solve for x
x=10
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2x-21+x=9
Add x to both sides.
3x-21=9
Combine 2x and x to get 3x.
3x=9+21
Add 21 to both sides.
3x=30
Add 9 and 21 to get 30.
x=\frac{30}{3}
Divide both sides by 3.
x=10
Divide 30 by 3 to get 10.
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