Solve the system by addition. x + y = 4 –x + y = 2?

Question

Solve the system by addition. x + y = 4 –x + y = 2

Answer 1

x + y = 4
–x + y = 2
__________
Adding the two equations, you get

2y=6 --> y=3

Sub this value back into the first equation (y=3)
x + y = 4
x + (3)= 4
x=1

Therefore, x=1, y=3

Answer 2

x + y = 4
y = 4 - x

- x + y = 2
y = x + 2

x + 2 = 4 - x
2x = 2
x = 1

y = 1 + 2
y = 3

Answer: x = 1, y = 3

Proof:
1 + 3 = 4

- 1 + 3 = 2