Question

How do you solve `21- ( x + 9) = 8x - 6?`

Answer 1

`x = 2`

Explanation:

First, expand the term in parenthesis and then group and combine like terms on the left side of the equation:

`21 - x - 9 = 8x - 6`

`21 - 9 - x = 8x - 6`

`12 - x = 8x - 6`

Now, isolate the `x` terms on one side of the equation and the constants on the other side of the equation while keeping the equation balanced:

`12 - x + x + 6 = 8x + x - 6 + 6`

`12 - 0 + 6 = (8 + 1)x - 0`

`12 + 6 = 9x`

`18 = 9x`

Now solve for `x` while keeping the equation balanced:

`18/9 = (9x)/9`

`2 = (cancel(9)x)/cancel(9)`

`2 = x`