Question

Solve using addition - x - y =4, x + 2y =4

Answer 1

When you add the two equations, the x's cancel out leaving 0x (so no x is left) the rest of the equation simplifies to

y = 8

Answer 2

For this case we have a system of two equations with two unknowns, given by the variables x and y respectively. To solve we follow the steps below:

1st step:

We eliminate a variable, for this we add both equations

$-x-y = 4\\x + 2y = 4\\-x + x-y + 2y = 4 + 4\\y = 8$

Step 2:

We substitute the value of "y" in any of the equations and clear x:

$-x-8 = 4\\-x = 4 + 8\\-x = 12\\x = -12$

Thus, the values of the variables are given by:

$x = -12\\y = 8$

Answer:

$x = -12\\y = 8$