anonymous one year ago This is the only question on the entire quiz I don't get. Will fan + medal, please help!!! A student is trying to solve the system of two equations given below: Equation P: x + y = 8 Equation Q: 2x + 5y = 24 Which of the following steps can be used to eliminate the x term? 2(x + y = 8) −2(x + y = 8) −1(2x + 5y = 24) −2(2x + 5y = 24)

1. amistre64

what does it mean to eliminate something?

2. anonymous

@amistre64 To get rid of?

3. amistre64

yeah, or in math terms .. make it go to zero

4. amistre64

so, what are our x terms in this case?

5. anonymous

@amistre64 2x and x?

6. amistre64

youre doing fine, yes now, what would you propose we do to eliminate them? what would we multiply one by such that when we add them together we get zero?

7. anonymous

I wanna say 8 because if we're multiplying 1, 1 x 8 is 8. But at the same time I feel like that's wrong?

8. amistre64

hmm, 8 isnt in our options so your feeling is spot on ... let "n" be some number such that: 2x + nx = 0, fpr all values of x (2+n)x = 0 any more ideas?

9. anonymous

Oh! I was looking at the first equation. Would it be 5 then?

10. anonymous

Or 2? Since we're trying to get rid of the x...(I'm sorry I know I'm really slow in math)

11. amistre64

2 is closer :) lets try it out (2+2)x = 0 4x = 0, this is not true for all x when is 2+n = 0 ?

12. anonymous

2+n = 0 when n = -2, right?

13. amistre64

that better, yes so what this tells us is that we want to multiply by a -2 the last thing to determine is which equation should we multiply by -2?

14. anonymous

Equation Q because if we solve that one first we can just replace the x and y variables in question P?

15. amistre64

well, equation Q already has 2x in it ... so we really want to leave it as is. this leaves us with equation P. -2(x+...) = -2x + ... now when we combine (add) -2P and Q we get -2x + ... 2x + ... --------- 0x + ... and our x term has been eliminated.

16. amistre64

so, which option should we pick now?

17. anonymous

B?

18. amistre64

hmm, your post does not letter them, but i would agree with the second option yes

19. anonymous

Oh, sorry! Also do you mind if I save this? Like your responses? You helped me a lot

20. amistre64

save what you want :)

21. anonymous

Thank you for helping me!!!

22. amistre64

youre welcome, and good luck :)