Question

What is the solution of the following system?
3x + 3y = 10
-9x - 9y = -20

My work so far:
3x + 3y = 10
-9x - 9y = -30
-6x -6y = -20

This problem is different from the other one, so I'm not really sure how to do it. Whoever can help me on this will receive fan and medal :) thank you all in advance!

Answer 1

Are you looking for the x and y coordinates?

Answer 2

Yes :)

Answer 3

I don't think I'm doing this right and if I am, I'm not sure where to move on from there.

Answer 4

@Ray1998 instead of multiplying equation one by -3, multiply it by 3

3x + 3y = 10 ----> 9x + 9y = 30

so we have this system

9x + 9y = -30
-9x - 9y = -20

add the equations to get

9x + 9y = -30
-9x - 9y = -20
--------------
0x+0y = -50


we end up with 0 = -50 which is never true. There are no (x,y) values that make 0 = -50 true. So we have an inconsistent system that has no solutions.

Answer 5

oops I made a typo, I put -30 instead of 30

3x + 3y = 10 ----> 9x + 9y = 30


9x + 9y = 30
-9x - 9y = -20
--------------
0x+0y = 10

which leads to 0 = 10

the system is still inconsistent

Answer 6

Okay, I think I understand what you are saying, but what happens to the 3x + 3y = 10 equation? @jim_thompson5910

Answer 7

Nevermind! I see now lol. @jim_thompson5910

Answer 8

when I multiplied both sides by 3, it turned into 9x + 9y = 30

Answer 9

ok great

Answer 10

Thank you for all your help! This was great :)

Answer 11

you're welcome