Question

*MEDAL*
Solve.
2x +6y = -12

Answer 1

2x +6y =-12
2x = -12 -6y
x = (12-6y)
-------
2

substitute that statement for x

2(12-6y) +6y = -12
----
2

factor left side
24 - 12y +6y = -12
solve for y
then solve for x

Answer 2

24 -6y =-12
24 + 12 = 6y
36 = 6y
6 = y
insert 6 for y and solve for x

Answer 3

24 - 18y = -12
(add 24 to each side)
-18y = -36
(divide -18 by each side)

y = 2?

Answer 4

What are you solving for?

Answer 5

Both, i guess. both x and y.

Answer 6

no
add 18y to both sides
ad 12 to both sides to get:
36 = 6y

Answer 7

Hard to believe thats the question (solving for both)

Answer 8

you cant add 24 to get rid of 24

Answer 9

ooh, so now divide 6 by each side.
So y = 6

Answer 10

yes

Answer 11

insert 6 for y and solve for x

Answer 12

So now it's 2x + 6(6) = -12?

Answer 13

yup

Answer 14

you got this

Answer 15

2x + 36 = -12
-36 -36
___________________
2x = -48
2 2

x = -24

I feel like I did something wrong...

Answer 16

looks good to me
2(-24) + 36 = -12
-48 + 36 = -12
-12 = -12

Answer 17

my question is what do you need to solve for.... which letter...

my next question is... is there another equation....?

you cannot solve 2 equation with 2 unknowns......

Answer 18

Thanks :D

Answer 19

You can use this technique to solve for three variables too, it's wold

Answer 20

(wild)

Answer 21

The original question is this:
@campbell_st

Answer 22

campbell, you can solve for 2 or 3 unknowns easily with the right tools

Answer 23

what happens if x = 0 and y = -2.... thats a solution it gives an answer of -12

along with x = -12 and y = 1 that gives an answer of -12

Answer 24

thats better, you are solving 2 equations in 2 unknowns so you should get a unqique solution

Answer 25

that is A possible solution but not THE solution.
Because when you solve for the first step:
x = (12-6y)
-------
2
you would have gotten a different equation if it were your numbers

Answer 26

Choices:
(2, 1)
(0, -2)
(-2, 0)
(1, 2)

Answer 27

multiply the 1st equation by 5 and the 2nd equation by 6, this will allow you to eliminate y. add the 2 new equations

10x + 30y = -60
30x - 30y = 60
------------------
40x = 0

x = 0

subsitute into either of the original equations to find y

hope this helps

Answer 28

it does. By ruling other options out (since other then 1 has x = 0), then it would be (0, -2). B.

Answer 29

well well well, I wasn't shown the second equation
that narrows it down and campbell is right
Special you have to present all the info

Answer 30

@ehuman, I agree with the right skills or tools you can solve anything.... but you cannot solve 1 equation with 2 unknowns. All you can do is change the subject

Answer 31

thats correct well done

Answer 32

sorry, I just in year 10 maths.... and have to et back to my work

Answer 33

Insert the first solved variable into the second equation to get the correct answer

Answer 34

Sorry, @ehuman .
My friend showed me this way of working this where if you figure out the first problem, it should rule out the other 3 options. Meh, didn't work with this one! Haha

Answer 35

actually substituting into either of the original equations will give the correct solution. You are really finding the point on the number plane where the 2 lines intersect.