Question

how do you solve for this?
-2x - y = 4
2x + y = -2

-8x + 4y = -16
-4x + 2y = -8


x - 2y = 6
-2x + y = 4


2x + 3y = 6
3x + 2y = 4
which one corresponds to the given graph

Answer 1

hint: the lines are parallel so the system of equations will have no solution

Answer 2

yeah but that's not a choice

Answer 3

well which system has no solutions?

Answer 4

idk that's what im looking for

Answer 5

let's focus on choice D

Answer 6

solving 2x + 3y = 6 for y gives us

2x + 3y = 6

3y = -2x + 6

y = -2/3x + 6/3

y = -2/3x + 2

so the slope of this line is -2/3

Answer 7

solving 3x + 2y = 4 for y gets you

3x + 2y = 4

2y = -3x + 4

y = -3/2x + 4/2

y = -3/2x + 2

and the slope here is -3/2

Answer 8

the two slopes are NOT equal, so this means that the two lines will intersect somewhere leading to exactly one solution

so D is out since we want a system with no solutions

Answer 9

so d is wrong. okay what about b?

Answer 10

what's the slope of -8x + 4y = -16

Answer 11

I really don't know how to solve for slope

Answer 12

solve for y and tell me what you get

Answer 13

y=2x-4

Answer 14

so the slope here is what?

Answer 15

2,-4?

Answer 16

it's the number in front of the x, so 2

Answer 17

if you solve -4x + 2y = -8 for y, you get

-4x + 2y = -8

2y = 4x-8

y = 4x/2 - 8/2

y = 2x - 4

and this is the *exact* same equation you get when you solve -8 x + 4 y = -16 for y

so essentially -8x + 4y = -16 and -4x + 2y = -8 are the exact same equation and graph the same exact line

so they are NOT parallel lines that never cross

so B is out too

Answer 18

making sense so far?

Answer 19

yes, maybe c?

Answer 20

let's see, what do you get when you solve x - 2y = 6 for y?

Answer 21

im stuck.. I got -2y=-1x+6
and divide by -2,i got stuck on that

Answer 22

x - 2y = 6

-2y = -x + 6

y = -x/(-2) + 6/(-2)

y = 1/2x - 3

so the slope here is 1/2

Answer 23

what do you get when you solve -2x + y = 4 for y ?

Answer 24

y=2x+4

Answer 25

the slope here is _____

Answer 26

2

Answer 27

the two slopes are NOT equal, so the two lines are NOT parallel

Answer 28

so its a

Answer 29

so choice C is out leaving A to be the answer

Answer 30

and if you found the slopes of the equations in choice A, you'd find they were the same slope

you'd also find that the equations (after solving for y) were different, so they wouldn't be the same exact equation (like you got in choice B)

Answer 31

so that would point to the fact the two lines were parallel and never crossed

Answer 32

okay thank you

Answer 33

you're welcome