## anonymous one year ago y = 8x − 9 y = 4x − 1 Part A: Explain how you will solve the pair of equations by substitution or elimination. Show all the steps and write the solution. Part B: If the two equations are graphed, at what point will the lines representing the two equations intersect? Explain your answer.

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1. anonymous

what is a variable that u can eliminate?

2. anonymous

X? I think. I'm completely lost

3. anonymous

treat this as an equation

4. anonymous

You can add or subtract to eliminate a letter (x or y).

5. anonymous

$\frac{ y=8x-9 } { y=4x-1 }$

6. anonymous

so can you see any thing that can be eliminated by subtraction or addition?

7. anonymous

hello??

8. anonymous

9-1??? Sorry I didn't reply I got sidetracked

9. anonymous

do u know wit a variable is?

10. anonymous

@andrea0529

11. anonymous

I'm sorry I really need help I suck at math pls

12. UsukiDoll

For part B, we graph these two equations y=8x-9 and y= 4x-1 then the point of intersection is when there is a solution for both of these equations

13. UsukiDoll

For part A. substitution is a better choice.

14. anonymous

u can eliminate y

15. anonymous

so it becomes $\frac{ 8x-9 }{ 4x-1 }$

16. anonymous

Why would you say that I came on here for help because I care about my education not to be insulted by rude people like you.

17. UsukiDoll

and how the heck can you solve with that?

18. UsukiDoll

anyway set these two equations together 8x-9 = 4x-1 put all variables to the left and all numbers to the right 8x-4x=-1+9 now what's 8x-4x and what's -1+9 ?

19. anonymous

Fine I don't want your help. You didn't hack me shut up.

20. UsukiDoll

-_- ughhhh @ganeshie8

21. UsukiDoll

@Icedragon50 stop creating drama on here. Just leave if you can't help nicely to other OS users.

22. anonymous

Thank you @usukidoll for actually helping me

23. anonymous

$8x-y=9$$4x-y=1$

24. anonymous

looking it this way might help

25. UsukiDoll

@saseal that works too elimination or substitution can give the same results.

26. anonymous

-1+9=8 thanks so much

27. UsukiDoll

forgot one part though 8x-4x=-1+9 now what's 8x-4x and what's -1+9 ? what's 8x-4x ?

28. anonymous

yea its easier to put in matrix form that way :)

29. UsukiDoll

true, but most of the time , matrix form versions are taught way later o_O.

30. UsukiDoll

@andrea0529 what's 8x-4x ? or an easier way to put it by factoring the x x(8-4) what's 8-4 ?

31. anonymous

4x

32. anonymous

yea, once you go matrix you dont go back!

33. UsukiDoll

:) so now we have 4x = 8 we divide 4 from both sides so what's 8/4 ?

34. UsukiDoll

8 divided by 4 @andrea0529 then we have x by itself after that step.

35. UsukiDoll

|dw:1438679720781:dw|

36. anonymous

8/4=2 so x=2

37. UsukiDoll

yes so now that we have x = 2 , we can plug it into one of the equations to solve for y let's pick the second equation y=4x-1 so we plug in x = 2 into y = 4x-1 y=4(2)-1 y=8-1 = ? what's 8-1 ?

38. anonymous

8-1=7

39. UsukiDoll

mhm so x = 2 and y = 7 we can plug these numbers back to the equation to see if they hold true. That means we have done this correctly

40. UsukiDoll

7=4(2)-1 7=8-1 7=7 7=8(2)-9 7=16-9 7=7

41. UsukiDoll

so we have done this correctly. Apparently at the point (2,7) the two lines should intersect

42. UsukiDoll

but it's asking for a graph so we need to make tables... -_- we can let x = 0,1,2 to solve for y for y = 8x-9 and y = 4x-1

43. UsukiDoll

|dw:1438680048402:dw| so for this chart we plug in x= 0 for those 2 equations... similarly plug in x = 1 for those two equations as well until we hit the x = 2 which results in 7 for both equations

44. UsukiDoll

|dw:1438680137485:dw| so can you plug x = 0 for y = 8x-9 y=4x-1 and can you plug x = 1 for y=8x-9 y=4x-1 ??? since x = 2 is done already, I've wrote y = 7 on both of them.

45. anonymous

46. UsukiDoll

yeah what this guy wrote ^

47. UsukiDoll

because graphing manually is a pain. I think I overshot part b. oh well .

48. UsukiDoll

but (2,7) is a point that two lines cross (point of intersection) and there is one solution when we have perpendicular lines.

49. UsukiDoll

@andrea0529 overshot part b. it was just asking the point of intersection with is (2,7) .

50. anonymous

Okay I get it know I mostly needed help with part a. I've got part b. Thank you so much.☺️