Solve for x
x=7
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x\times 0.12=4\times 0.21
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 4x, the least common multiple of 4,x.
x\times 0.12=0.84
Multiply 4 and 0.21 to get 0.84.
x=\frac{0.84}{0.12}
Divide both sides by 0.12.
x=\frac{84}{12}
Expand \frac{0.84}{0.12} by multiplying both numerator and the denominator by 100.
x=7
Divide 84 by 12 to get 7.
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