Solve for x
x=3
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15+x+x=21
Add x to both sides.
15+2x=21
Combine x and x to get 2x.
2x=21-15
Subtract 15 from both sides.
2x=6
Subtract 15 from 21 to get 6.
x=\frac{6}{2}
Divide both sides by 2.
x=3
Divide 6 by 2 to get 3.
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