Solve for x
x = \frac{15}{4} = 3\frac{3}{4} = 3.75
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x+3+3x=18
Add 3x to both sides.
4x+3=18
Combine x and 3x to get 4x.
4x=18-3
Subtract 3 from both sides.
4x=15
Subtract 3 from 18 to get 15.
x=\frac{15}{4}
Divide both sides by 4.
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