Question

how do i solve by substituting
x +y = 6
y = 4

Answer 1

Since we alredy know that y = 6 we can go ahead and insert it into the problem. It would look like this:

x + 4 = 6

Now we can begin to solve.

Since positive 4 is on one side, we can subtract it from both sides

It will look like this:

x + 4 = 6

x - 4 = 6 - 4

You end up with

x = 2

Now substitute all your known variables.

It will look like

2 + 4 = 6

This equation is true.

Answer 2

you plug the Y=4 into the equations Y.
so here:
x+y=6
x+4=6

Now you will take the new problem and get X by itself so you can later solve for Y.

x+4=6
-4. -4
_______
x=2

now take your X=2 and plug it in for your X in the problem:
x+y=6
2+y=6


Now get Y alone like you got X:

2+y=6
-2. -2
_______
y=4

So now your answers will be:
x=2 and y=4 (graphed: x,y so it would be 2,4)

To check yourself with this, just plug both of your numbers into the equation and see if you get: 6=6 that is how you know your answers are correct.