Solve for x
x=60
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420-4x=3x
Multiply both sides of the equation by 12, the least common multiple of 3,4.
420-4x-3x=0
Subtract 3x from both sides.
420-7x=0
Combine -4x and -3x to get -7x.
-7x=-420
Subtract 420 from both sides. Anything subtracted from zero gives its negation.
x=\frac{-420}{-7}
Divide both sides by -7.
x=60
Divide -420 by -7 to get 60.
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