Question

**WILL MEDAL**
Which ordered pair is the solution to the system of equations?
-3x+4y=-20
x+4y=-4


A.
(8, 1)

B.
(−12, 2)

C.
(−4, −8)

D.
(4, −2)

Answer 1

so two ways, one just plug in the points and see if they work, 2 solve the system. Would you like to learn how?

Answer 2

Um duh

Answer 3

Lol jk

Answer 4

ok, well, I have to check sometimes you get just answer people and I'm sick of wasting my time on them

Answer 5

So, ready to work with me?

Answer 6

Yea ig

Answer 7

ok, so, you want to pick any equation, and decide whether you want to solve for y or x

Answer 8

which do you prefer

Answer 9

y first

Answer 10

ok, so I recommend solving the top equation for y first then, do you know how to do that?

Answer 11

Not really

Answer 12

ok, np, so we are going to solve \[-3x+4y=-20\] for y. Our first step is to "undo" the addition of \(-3x\) on the left side do you have any ideas on what we can do?

Answer 13

Add 3 to both sides?

Answer 14

well, almost, we need to get rid of the -3x, so, we add +3x to both sides, can you try that for me please?

Answer 15

4y=-23?

Answer 16

well, we can't add -20 and 3x because they are not like terms, so we literally just say \[4y=-20+3x\] Does that make sense?

Answer 17

Oh yes

Answer 18

ok, so now, what's your next step to get y by itself?

Answer 19

So 4y=-23x?

Answer 20

nope, since -20 doesn't have an x, we cannot add an x term to it.(Just an fyi, if we did -20+3=-17)

Answer 21

You are using common core eh? I'll be back in like 2 minutes, I have to go take out a load of laundry, but I'll teach you as soon as I get back. Can you please watch this video on solving a system of equations for me while I'm gone? https://www.khanacademy.org/math/algebra/systems-of-eq-and-ineq/fast-systems-of-equations/v/solving-linear-systems-by-substitution

Answer 22

So would it be C?

Answer 23

I don't think that -4+4*-8=-4 Do you?

Answer 24

So, did you check out the video?

Answer 25

Yea now I think it's b

Answer 26

does -3*-12+4*2=-20?

Answer 27

No it's 44

Answer 28

so that can't be the answer since it doesn't wok for both equations, since we are currently doing a guess and check style, try A, Does it work?

Answer 29

Yes?

Answer 30

try it and show me

Answer 31

put it into the second and see if it works

Answer 32

does 8+4*1=-4?

Answer 33

No 12

Answer 34

ok, so does A work?

Answer 35

No

Answer 36

ok, so try our last one, Does D work, test it in both equations and show me here

Answer 37

Finally answer-->D

Answer 38

Does it work? Show me, we haven't solved anything

Answer 39

I gtg now

Answer 40

But thx anyways

Answer 41

....

Answer 42

yw I guess