Add like terms on the same side:
-10 + 8x = -56
Add ten to both sides
-10 + 8x + 10 = -56 +10
Simplify:
8x = -46
Divide both side by 8
8x/8 = -46/8
Simplify
x = - 5.75
The answer is x = -5.75
(The answer can also be written as -23/4 or -5 3/4)
The area of a parallelogram can be found in the same way as that of a rectangle, so base x height. To find the base we have to do area ÷ height or 18 1/3 ÷ 3 1/3= 5.5 feet