SOLUTION: how do you solve 21=1/2(8x-18)-x? I know x=10 but I don't know the proper way of getting the answer.

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Question 253306: how do you solve 21=1/2(8x-18)-x? I know x=10 but I don't know the proper way of getting the answer.
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
take it step by step
The first thing to do is get rid of the parentheses. How?
multiply out 1/2(8x-18)
1/2 *8x=4x
1/2(-18)=-9
don't forget the minus sign
so now we have 21=4x-9-x
combine terms
21=3x-9
add 9 to both sides
30=3x
10=x