Question

3x-6x=8
4x-8y=12
multiply the 1st by -4 and the 2nd by 3 and add results. How do I do that?

Answer 1

3x - 6y = 8
4x - 8y = 12

-4(3x - 6y) = -4(8)
3(4x - 8y) = 3(12)

Answer 2

-12x-12y=-32
12x-24y=36
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then I just add them together right?

Answer 3

Yes. Ad the. Notice your 12x's will cancel.

Answer 4

-12x-24y=-32
12x-24y= 36
+--------------
-48y=4 is my answer but my multiple choices are:
a)2y=-2 b)6y=6 c)0=0 d)0=4 I think d) but where did I go wrong? A negative and a negative need to be added.

Answer 5

You have -48y = 4
Now solve for y

Answer 6

i. 3x-6x=8
4x-8y=12


ii
-4(3x - 6y) = 8
3(4x - 8y) = 12

iii.
-12x + 24y = -32
12x - 24y = 36

iv.
Now we simply add
12x -12x + 24y - 24y = 36 - 32

Answer 7

I see it this way. Thanks a lot for your help. Wish I would've found this sight yesterday. I have been working on this worksheet for three days and I'm only on #9. Let's see how goes the next few problems.

Answer 8

Well, welcome to OpenStudy! Ask anything you want and feel free to tag me!

Answer 9

Thanks!