Solve for r
r=28
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5r=7\times 20
Variable r cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 7r, the least common multiple of 7,r.
5r=140
Multiply 7 and 20 to get 140.
r=\frac{140}{5}
Divide both sides by 5.
r=28
Divide 140 by 5 to get 28.
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