Here's how to find the value of x:
9 - 0.75 ( x + 8 ) - 5 = -6.5 find the difference of 9 - 0.75
8.25 ( x + 8 ) - 5 = -6.5 add 5 to both sides
8.25 ( x + 8 ) = -1.5 distribute 8.25 to x and 8
8.25x + 66 = -1.5 subtract 66 from both sides
8.25x = -67.5 divide both sides by 8.25
x = 18.18181818...... the value of x is 18 2/11
hope this helps