Question

Worked this on my own, not sure of my answer is correct....?

What is a possible first step to eliminate the variable y in the following system?4x + 6y = 15x - 3y = 8


Multiply the first equation by 5.

Multiply the first equation by -2.

Multiply the second equation by 2.

Multiply the second equation by -3.

Answer 1

multiply the second equation by 2

Answer 2

I got b, though? why not -2?

Answer 3

then, you can subtract both the equations easily eliminating the y-term

Answer 4

Sorry, add

Answer 5

If you do as in b, then you will have to subtract the equations and you will have one extra step than doing as in c.

Answer 6

Hey, wait...i thought "b" to multiply second equation(didn't have a proper look) by -2.

Answer 7

I am sorry...now i'll show you what happens if you proceed as in b...

Answer 8

Thank you

Answer 9

If you multiply the first equation by -2, it becomes -8x-12y= -16 and we have second equation as 15x-3y=8. its not possible to solve it unless you multiply second equation by 4. Its quite lengthy...

Answer 10

Oh, i see what you're saying

Answer 11

So the question is asking for the most ACCURATE, yet SIMPLE approach?

Answer 12

If you do as in c, the second equation becomes 30x-6y=16 and the first equation as given is 4x+3y=8 and now its easy to solve...yes simple and accurate approach

Answer 13

4x+6y=8 i made a typo above..

Answer 14

The answer I get is C

Answer 15

4x+6y=8 is not one of the equations.

Answer 16

So, you are good..you are the first person on this site who wanna learn, as far as i've experienced...yes its C

Answer 17

awwww thank you!!!!!!:))))

Answer 18

@CliffSedge According to your master theory, you are right but I gave a solution to the question represented irrespective of the error made by her professor

Answer 19

Which is? @AbhimanyuPudi

Answer 20

Yes. Your answer was correct, but I wanted to make sure we all know what's really going on here.

Answer 21

well, the error as found out by our partner is that they are not compound equations..