115k views
5 votes
How do you solve x-y=1 ; x+y=3. Please Explain

User Svdree
by
7.7k points

2 Answers

1 vote
x - y = 1
x + y = 3
________
2x = 4
__ _
2 2
x = 2
x + y = 3
2 + y = 3
-2 -2
________
y = 1
(x, y) = (2, 1)
User Didats Triadi
by
8.8k points
2 votes
You isolate one variable. Let's say that x will be that variable in the first equation:
x-y=1
+y +y
x=y+1
So now you have the equation for x. All you have to do is substitute it into the other:
x=y+1
(y+1)+y=3
Combine like terms and solve:
2y+1=3
-1 -1
2y=2
2y/2=2/2
y=1
Now that you have the value of one, substitute it into either of the equations to find x.
If you put it in the first:
x-1=1
+1 +1
x=2
If you put it into the other, you would get the same answer.
Therefore, y=1 and x=2
User Janovak
by
9.0k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories