5.4k views
15 votes
2x-y=7
x+y=5

Use elimination

User Pawel Maga
by
7.7k points

1 Answer

6 votes

Answer: (x,y) = (4,1)

In other words, x = 4 and y = 1

==============================================

Step-by-step explanation:

Add the equations straight down.

  • The x terms add to 3x because 2x+x = 3x
  • The y terms go away when you add them since -y+y = 0y = 0
  • The terms on the right hand sides add to 7+5 = 12

After those three sets of adding terms, we end up with 3x = 12. This solves to x = 4 when you divide both sides by 3.

Use this x value to find y.

2x-y = 7

2(4)-y = 7

8-y = 7

-y = 7-8

-y = -1

y = 1

or

x+y = 5

4+y = 5

y = 5-4

y = 1

Your best best is probably to use the second equation, but it doesn't hurt to have practice with both equations. Getting the same y value helps confirm we have the correct x value.

Therefore, the solution is the ordered pair (x,y) = (4,1). Meaning that x = 4 and y = 1 pair up together.

Visual confirmation can be done by using a graphing tool like Desmos. The two lines intersect at (4, 1). See below.

2x-y=7 x+y=5 Use elimination-example-1
User Thejustv
by
8.3k 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