7+x, because the sum means adding.
Answer:
V = 168 cm^3
Step-by-step explanation:
L length - 8cm
W width - 3 cm
H height - 7 cm
V = w h l (Right rectangular prism)
For this case we have that by definition, a function is of the form:

So, we have the following system of equations:

Equating the equations we have:

Adding 2x to both sides of the equation:

Subtracting 2 from both sides of the equation:

Dividing between -4 on both sides of the equation:

Thus, the value of the variable "x" is -0.5.
Answer:
-0.5