Question

solve using elimination 2x+4y=-4 and 3x+5y=-3

Answer 1

don't be offended I am just figuring out where to start at, but do you know the general process of elimination and need help with this one or need help understanding elimination in general?

Answer 2

I need help solving it. I cant seem to figure it out

Answer 3

well first you need to choose one variable to eliminate since none of these work together nicely i would suggest eliminating x as it has the lowest coefficents

Answer 4

how do I do that??

Answer 5

so you need to find the lowest common multiple of the coefficients of x
3 and 2

Answer 6

so like 6

Answer 7

\[2x+4y=-4[1]\]
\[3x+5y=-3[2]\]
\[[1]\times3\]
\[3(2x+4y)=3(-4)\]
\[6x+12y=-12[3]\]
\[[2]\times2\]
\[2(3x+5y)=2(-3)\]
\[6x+10y=-6[4]\]
\[[3]-[4]\]
\[(6x+12y)-(6x+10y)=(−12)-(-6)\]
\[6x+12y-6x-10y=-12--6\]
Collect like terms
\[2y=-12+6\]

Answer 8

Do the rest.

Answer 9

To find x substitute the y value into any one of the 4 equations labelled above.

Answer 10

yes now multiply the first equation by 6/2=3 and the second equation by 6/3=2

Answer 11

@Azteck its better if you help them through the problem instead of just posting the work

Answer 12

@hannahbaker do you still want my help?

Answer 13

@whatisthequestion yes very much please :) the @Azteck confused me

Answer 14

@whatisthequestion I think you should continue helping. Sorry.

Answer 15

its fine just for future reference

Answer 16

@hannahbaker And that's the clearest step by step working you can get. There's nothing confusing about that. Once you conquer this topic, you will look back at that and think, "Wow, that is one of the most detailed and simple worked solution."

Answer 17

@hannahbaker can you tell me what the first equation and second equation are multiplied by 3 and 2 respectively? I explained why those numbers earlier.

Answer 18

@Azteck It looks so different in my head

Answer 19

6x+12y=-12 and -6-10y=6

Answer 20

@Azteck unfortunately thats not enough for alot of people otherwise schools would not have teachers just textbooks and reading them would be enough

Answer 21

Reread my post. I said "Once you conquer"

Answer 22

Once you conquer means that once you've learnt and understood the concepts from teachers/textbooks. Whatever makes you completely understand the topic.

Answer 23

probably just a typo but you don't have an x in your second equation

Answer 24

oops... I meant -6x

Answer 25

so the x's cancel out

Answer 26

okay since you already isolated multiplied the second equation by -1 we can just add the two equations to cancel the xs . . which you just posted

Answer 27

and now its just... 2y=-6

Answer 28

correct

Answer 29

once you solve for y you can plug that value into equation 1 or 2 and solve for x

Answer 30

ok then it becomes y=-3 right

Answer 31

yup

Answer 32

Well glad I could help please don't forget to award the medal to whomever helped you most and close the question.