Answer:
y = 3z - 2x
Explanation:
Systems of equations can be solved by a number of know techniques, such as substitution, elimination or graphical approach.
We are required to solve the system of equations given via substitution;
2x + y = 3z
x + y = 6z
The question requires us to determine the value for y from the first equation, that could be substituted into the second equation.
We simply need to make y the subject of the formula from the first equation;
2x + y = 3z
To do this we subtract 2x on both sides of the equation;
2x + y -2x = 3z - 2x
y = 3z - 2x
This is the value of y from the first equation, that can be substituted into the second equation.