Consider the system.
6x − 3y = 42
x + 3y = −21

Part 1 out of 2
Complete the description for three different substitution methods that can be used to solve this system.

Solve the second equation for x (x =
-21
− 3y) and then substitute the value into the first equation.
Solve the first equation for y (y = 2x −
-14
) and then substitute that value into the second equation.
Solve either equation for 3y (3y =
− x or 3y = 6x −
) and then substitute that value into the other equation.