The answer is -3.
To find this, we simply have to solve the equation and leave only the blank and the parenthesis that it is with on the right side. Then we can divide by the parenthesis. The work for this is done for you below.
____(x - 3) + 2x = -(x - 5) + 4 ----> Distribute the -1 to the parenthesis.
____(x + 3) + 2x = -x + 5 + 4 ----> Simplify
____(x + 3) + 2x = -x + 9 ----> Subtract 2x from both sides
____(x + 3) = -3x + 9 ------> Divide both sides by x + 3
____ = -3.
So the equation would be 4\100 of 1800 every year = (4/100x1800)x8 years = 72x8 years = $576. Best of luck!
7/12 as a decimal is 0.583333333
or 0.59
Hope this helps ;)