Question

Can someone please help me answer this question
Find the solution to the system below~
x - y = 0
3x + y = -4

Answer 1

@jim_thompson5910 could you try to help me?

Answer 2

notice how if you added straight down, you'd have

x plus 3x = 4x
-y plus y = 0y which is the same as 0, so it goes away
0 plus -4 = -4

so after adding straight down, we end up with 4x = -4

Answer 3

hopefully that makes sense?

Answer 4

well to be honest, no sir it really doesn't ... I've never learned to do it that way

Answer 5

which method has your teacher gone over?

Answer 6

graphing? substitution?

Answer 7

Graphing

Answer 8

@jim_thompson5910

Answer 9

ok let's graph each equation then

I would use desmos to graph

https://www.desmos.com/calculator

Answer 10

type each equation into each separate box

Answer 11

yes sir I did that but I didn't do the solution

Answer 12

once you have the 2 equations graphed, you can click the point of intersection to have the coordinates pop up

Answer 13

ok then what

Answer 14

what pops up?

Answer 15

(-1.333,0) (-1,-1)

Answer 16

I'm only interested in the point of intersection between the two lines, not the x intercept

the solution is (-1,-1)

so x = -1 and y = -1

Answer 17

oh ok, so for the solution all I put is (-1,-1)?
x = -1 and y = -1

Answer 18

@jim_thompson5910 ?

Answer 19

that is correct

Answer 20

OK, thank you so much for your help!!