SOLUTION: y+x=3 y+3x=-1 can you solve these linear equations by graphing? can you solve these linear equations by substitution? can you solve these linear equations by addition?

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Question 35282: y+x=3
y+3x=-1
can you solve these linear equations by graphing?
can you solve these linear equations by substitution?
can you solve these linear equations by addition?
Answer by elima(1433) (Show Source):
You can put this solution on YOUR website!
Sorry if we got to you to late. You can solve the equations by substitution and addition.
solve these linear equations by substitution;
y+x=3
y+3x=-1
First lets look at equation 1, solve for x;
y+x=3
x=3-y
Now substitute the answer for x in equation 2;
y+3(3-y)=-1
y+9-3y=-1
-2y=-10
y=5
Now that you have an answer for y, lets solve for x;
(5)+x=3
x=-2
So the answer for this would be;
x=-2; y=5
solve these linear equations by addition;
Lets add the two equations together;
y+x=3
y+3x=-1
----------
When we add them together we want to get rid of one variable or make it =0;
so we will multiply -1 to equation 2;
(-1)y+3x=-1
-y-3x=1
Now we will go back to adding the equations together;
y+x=3
-y-3x=1
-------
-2x=4
x=-2
Now plug that answer into one of the equations to get y;
y+(-2)=3
y=5
So answer;
x=-2; y=5
I hope you understand this, It is hard to explain additon.
=)