Solve for x
x=-2
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2x+9-8x=21
Subtract 8x from both sides.
-6x+9=21
Combine 2x and -8x to get -6x.
-6x=21-9
Subtract 9 from both sides.
-6x=12
Subtract 9 from 21 to get 12.
x=\frac{12}{-6}
Divide both sides by -6.
x=-2
Divide 12 by -6 to get -2.
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