Using a system of equations, it is found that the expression for the combined total weight is given by:
Weight = 250x + 20(300 - x).
A system of equations is when two or more variables are related, and equations are built to find the values of each variable.
In this problem, the variables are:
There is a combined total of 300 tables and chairs in his truck, hence:
x + y = 300 -> y = 300 - x
His truck is filled with tables that weigh 250 pounds each and chairs that weigh 20 pounds each, hence the total weight is:
Weight = 250x + 20(300 - x).
More can be learned about a system of equations at https://brainly.com/question/24342899