Which method is most efficient in solving a system of linear equations when two equations have x values with opposite coiffiecent values ?

Elimination

Step-by-step explanation:

A system of equations is 2 or more equations for which the same x,y solution exists. We can solve the system in three ways: elimination, substitution, or graphing. Elimination is the best method when we have standard form equations and x values with opposite coefficients. This is so because the x variable will eliminate easily and allow us to solve for y.

So first you would have to work with the y's since they are consecutive angles.Consecutive angles would add up to 180 so the problem would be
5(y+11)^0+4y-10=180 then simplify
10+4y-10=180
4y=180
y=45
Then plug in the y for the top problem and the add the answer to the x problem and set them to 180 because they are also a linear pair and you should get your answer
I got x=34