Solve for x
x = \frac{21}{4} = 5\frac{1}{4} = 5.25
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2x+x+x=21
Combine x and x to get 2x.
3x+x=21
Combine 2x and x to get 3x.
4x=21
Combine 3x and x to get 4x.
x=\frac{21}{4}
Divide both sides by 4.
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