the reason I'm going to use elimination for the first one a. its because we were given two equations with coefficients and to solve for them, we need to eliminate one of the variables and solve for the other then use the answer for the non eliminated variable to solve for the eliminated variable and its quite easy to do so.
for b and c. I choose to use substitution method to answer the equations because the y equation was given to us. The easiest thing to do is just to substitute Y equation in the given equation and solve for your variables.
