SOLUTION: don't know why the substitution method my head wont engage in. I am a college student , this on is driving me crazy x+y=4,y=3x using substitution method. in need of serious help.

Question 557977: don't know why the substitution method my head wont engage in. I am a college student , this on is driving me crazy x+y=4,y=3x using substitution method. in need of serious help.
Found 2 solutions by Alan3354, josmiceli:
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
x+y=4,y=3x using substitution method.
---------
x+y=4
y=3x
-----
Sub for y in the 1st eqn, find x.
x + 3x = 4
4x = 4
x = 1
------
y = 3

Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
A simple example of substitution is:
(1)
(2)
Substitute (2) into (1)
You can do this because appears
in both equations
(1) with the substitution is:
(1)
(1)
(1)
(1)
and, since
(2)
(2)
(2)
-----------------
Here's your problem:
(1)
(2)
I will substitute (2) into (1)
(1)
(1)
(1)
and, since
(2)
(2)
(2)
So, the solution is the point (1,3)
Here's a plot of the lines
(1)
(2)

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