(05.05 LC)
If you were to use the substitution method to solve the following system, choose the new
equation after the expression equivalent to x from the second equation is substituted into
the first equation. (5 points)
3x + 2y = -21
x-3y=4
3(3y + 4) + 2y = -21
O 31-3y + 4) + 2y = -21
3x + 2(3y + 4) = -21
3x + 21-3y + 4) = -21