Solve for x
x=3
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21=7x
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by x.
7x=21
Swap sides so that all variable terms are on the left hand side.
x=\frac{21}{7}
Divide both sides by 7.
x=3
Divide 21 by 7 to get 3.
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