Solve for x
x=75
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120\times 15=\left(x+15\right)\times 20
Variable x cannot be equal to -15 since division by zero is not defined. Multiply both sides of the equation by 120\left(x+15\right), the least common multiple of 15+x,120.
1800=\left(x+15\right)\times 20
Multiply 120 and 15 to get 1800.
1800=20x+300
Use the distributive property to multiply x+15 by 20.
20x+300=1800
Swap sides so that all variable terms are on the left hand side.
20x=1800-300
Subtract 300 from both sides.
20x=1500
Subtract 300 from 1800 to get 1500.
x=\frac{1500}{20}
Divide both sides by 20.
x=75
Divide 1500 by 20 to get 75.
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