Answer:
Step-by-step explanation:
You would need to isolate the "X" variable because it is common in all 3 equations.
Make a systems of equations:
11x+13y=209
x+y=19
A variable is a quantity that may change within the context of a mathematical problem or experiment. Typically, we use a single letter to represent a variable. The letters x, y, and z are common generic symbols used for variables.
So basically for your expression:
8-x
Hope that helped