Show me the steps? plz show me how 2 do this?

Question

For the next eight problems, use the substitution method when solving the systems of equations.

11) Solve by using substitution.

y=x+3

y=2x-4

Answer 1

y=x+3

y=2x-4

x+3=2x-4

x-2x=-4-3

-x=-7

x=7

y=7+3

y=10

Answer 2

Here are the steps:

1)  Take one of your equations and isolate one of the variables.  In your case this is done for you.  You know that Y is equal to (X + 3).  

2)  Substitute the solution from 1, into your other equation.

X + 3 = 2X - 4

3 = X - 4

7 = X

3)  Now, take your solution and plug it into the first  equation and solve for your other variable.

Y = 7 + 3

Y = 10

Test to make sure your answer is correct in both equations showing X = 7 and Y = 10.

Equation 1)  10 = 7 + 3

                       10 = 10  Yeah it worked

Equation 2)   10 = 2(7) - 4

                        10 = 14 - 4

                         10 = 10  Yeah it worked...

You now know your answer is correct...

Answer 3

1) You can rewrite the first equation to look like this:

x= 3 - y

2) then you substitute that into the second equation like this:

y= 2(3-y) - 4

and solve for y :)