Solve for x
x=6
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9x+15+21=90
Combine 6x and 3x to get 9x.
9x+36=90
Add 15 and 21 to get 36.
9x=90-36
Subtract 36 from both sides.
9x=54
Subtract 36 from 90 to get 54.
x=\frac{54}{9}
Divide both sides by 9.
x=6
Divide 54 by 9 to get 6.
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