Answer: the solution to the system of equations is x = 12 and y = 16.
Step-by-step explanation: To solve this system of equations, you can use the method of substitution.
First, solve one of the equations for one of the variables. For example, you can solve the first equation for x:
2x + y = 40
2x = 40 - y
x = (40 - y)/2
Then, substitute this expression for x in the second equation:
x - 2y = -20
(40 - y)/2 - 2y = -20
Multiplying both sides by 2, we get:
40 - y - 4y = -40
-5y = -80
y = 16
Substituting this value for y in the first equation, we can solve for x:
2x + 16 = 40
2x = 24
x = 12
Therefore, the solution to the system of equations is x = 12 and y = 16.