Show that (2, 1) is a solution of the system of equations.
x + 3y = 5,
y = –x + 3

1. Substitute (2, 1) into x + 3y = 5 to get .____
Options: 1 + 32 = 5, 1 + 3(2) = 5, 2 + 31 = 5, 2 + 3(1) = 5

2. Simplify the equation to get ____
Options: 5 = 5 is true, 7 = 7 is true, 7 = 5 is false, 33 = 5 is false

3. Substitute (2, 1) into y = –x + 3 to get ____
Options: 1 = -(2) + 3, 1 = -(2 + 3), 2 = -(1) + 3, 2 = -(1 + 3)

4. Simplify the equation to get .____
Options: 1 = 1 is true, 1 = -1 is false, 2 = 2 is true, 2 = -2 is false