Question

help with this question:
solve with elimination.
6x+y=-10
3x-y=3

Answer 1

can you see that if you add these toghether the y variable will cancel out?

Answer 2

yes i did that
but after that is confusing

Answer 3

Well, it leaves other stuff - try to add them together.

Answer 4

well after adding i get, and hopefully you get: 9x=-7

Answer 5

Which means that the x is something, and when you know x - voila!

Answer 6

wait i eliminated the y's
then i got:
6x=-12 and
3x=3

Answer 7

how did you get that? if you add 6x+3x you get 9x right?

Answer 8

you add the 6x and the 3x and the -12 and the 3?

Answer 9

You didn't eliminate them, you added them together - do that with the rest as well:)

Answer 10

where is the negative 12 coming from?

Answer 11

6x+y=-10
3x-y=3
+
-------------
9x=-7

Answer 12

oh sorry the -10 was originally a -12, i typed it out wrong

Answer 13

okay anyway this is what you get:
6x+y=-12
3x-y=3
+
-------------
9x=-9

Answer 14

so it would be:
9x=-9, right

Answer 15

so x=-1

Answer 16

correct

Answer 17

now, just plug that into any of the equations and solve for y

Answer 18

i get 2

Answer 19

but the answer key says it should be -1 and -6

Answer 20

How do you get 2 then?

Answer 21

x=-1 which is correct.

Answer 22

i dont know

Answer 23

yes but i need a -6 too

Answer 24

Just write the equations again.
Then you write -1 where all the x-es are (its good to use () ).
Then solve it as a regular problem.

Answer 25

ok, thanks i got it

Answer 26

You can use whichever problem you want, but one is usually easier to solve. Woohoo!:D

Answer 27

Its also smart to check if both problems add up once you've got both of them.

Answer 28

thanks