answersLogoWhite

0

You need to be more clear about your question.

3x + 6y = 18

2x + 5y = 20

The two equations you give represent lines. I assume you're trying to find the point at which they intersect. There are various ways to work this out.

One technique is to multiply each equation by a factor that gives one of the two variables the same coefficient. For example, if we multiply the first equation by 2, and the second equation by 3, we get:

6x + 12y = 36

6x + 15y = 60

Then we can subtract one from the other, which gives us a solution for y:

[6x + 12y = 36]

- [6x + 15y = 60]

_______________

[0x - 3y = -24]

So -3y = -24, telling us that at the point of intersection, y = 8. We can then plug that back into one of the original equations and solve for x:

2x + 5y = 20

2x + 5(8) = 20

2x = 20 - 40

2x = -20

x = -10

So the lines intersect at the point (-10, 8).

Another way to work it out is to solve one of the equations for a single variable, and then plug it into the other one:

3x + 6y = 18

∴ x + 2y = 6

∴ x = 6 - 2y

2x + 5y = 20

∴ 2(6 - 2y) + 5y = 20

∴ 12 - 4y + 5y = 20

∴ y = 20 - 12

∴ y = 8

That gives us the value 8 for y, which we can once again plug in to either of the original equations to find x:

2x + 5y = 20

∴ 2x + 40 = 20

∴ 2x = -20

∴ x = -10

Once again telling us that the lines intersect at the point (-10, 8)

User Avatar

Wiki User

13y ago

Still curious? Ask our experts.

Chat with our AI personalities

RossRoss
Every question is just a happy little opportunity.
Chat with Ross
BlakeBlake
As your older brother, I've been where you are—maybe not exactly, but close enough.
Chat with Blake
FranFran
I've made my fair share of mistakes, and if I can help you avoid a few, I'd sure like to try.
Chat with Fran

Add your answer:

Earn +20 pts
Q: 3x plus 6y equals 18 2x plus 5y equals 20?
Write your answer...
Submit
Still have questions?
magnify glass
imp