Solve for x
x=-30
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\left(x+21\right)\times 10-x\times 3=0
Variable x cannot be equal to any of the values -21,0 since division by zero is not defined. Multiply both sides of the equation by x\left(x+21\right), the least common multiple of x,x+21.
10x+210-x\times 3=0
Use the distributive property to multiply x+21 by 10.
10x-x\times 3=-210
Subtract 210 from both sides. Anything subtracted from zero gives its negation.
10x-3x=-210
Multiply -1 and 3 to get -3.
7x=-210
Combine 10x and -3x to get 7x.
x=\frac{-210}{7}
Divide both sides by 7.
x=-30
Divide -210 by 7 to get -30.
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