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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
    • one year ago
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    what is a variable that u can eliminate?

  2. anonymous
    • one year ago
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    X? I think. I'm completely lost

  3. anonymous
    • one year ago
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    treat this as an equation

  4. anonymous
    • one year ago
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    You can add or subtract to eliminate a letter (x or y).

  5. anonymous
    • one year ago
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    \[\frac{ y=8x-9 } { y=4x-1 }\]

  6. anonymous
    • one year ago
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    so can you see any thing that can be eliminated by subtraction or addition?

  7. anonymous
    • one year ago
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    hello??

  8. anonymous
    • one year ago
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    9-1??? Sorry I didn't reply I got sidetracked

  9. anonymous
    • one year ago
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    do u know wit a variable is?

  10. anonymous
    • one year ago
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    @andrea0529

  11. anonymous
    • one year ago
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    I'm sorry I really need help I suck at math pls

  12. UsukiDoll
    • one year ago
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    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
    • one year ago
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    For part A. substitution is a better choice.

  14. anonymous
    • one year ago
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    u can eliminate y

  15. anonymous
    • one year ago
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    so it becomes \[\frac{ 8x-9 }{ 4x-1 }\]

  16. anonymous
    • one year ago
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    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
    • one year ago
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    and how the heck can you solve with that?

  18. UsukiDoll
    • one year ago
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    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
    • one year ago
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    Fine I don't want your help. You didn't hack me shut up.

  20. UsukiDoll
    • one year ago
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    -_- ughhhh @ganeshie8

  21. UsukiDoll
    • one year ago
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    @Icedragon50 stop creating drama on here. Just leave if you can't help nicely to other OS users.

  22. anonymous
    • one year ago
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    Thank you @usukidoll for actually helping me

  23. anonymous
    • one year ago
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    \[8x-y=9\]\[4x-y=1\]

  24. anonymous
    • one year ago
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    looking it this way might help

  25. UsukiDoll
    • one year ago
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    @saseal that works too elimination or substitution can give the same results.

  26. anonymous
    • one year ago
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    -1+9=8 thanks so much

  27. UsukiDoll
    • one year ago
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    forgot one part though 8x-4x=-1+9 now what's 8x-4x and what's -1+9 ? what's 8x-4x ?

  28. anonymous
    • one year ago
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    yea its easier to put in matrix form that way :)

  29. UsukiDoll
    • one year ago
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    true, but most of the time , matrix form versions are taught way later o_O.

  30. UsukiDoll
    • one year ago
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    @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
    • one year ago
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    4x

  32. anonymous
    • one year ago
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    yea, once you go matrix you dont go back!

  33. UsukiDoll
    • one year ago
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    :) so now we have 4x = 8 we divide 4 from both sides so what's 8/4 ?

  34. UsukiDoll
    • one year ago
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    8 divided by 4 @andrea0529 then we have x by itself after that step.

  35. UsukiDoll
    • one year ago
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    |dw:1438679720781:dw|

  36. anonymous
    • one year ago
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    8/4=2 so x=2

  37. UsukiDoll
    • one year ago
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    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
    • one year ago
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    8-1=7

  39. UsukiDoll
    • one year ago
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    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
    • one year ago
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    7=4(2)-1 7=8-1 7=7 7=8(2)-9 7=16-9 7=7

  41. UsukiDoll
    • one year ago
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    so we have done this correctly. Apparently at the point (2,7) the two lines should intersect

  42. UsukiDoll
    • one year ago
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    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
    • one year ago
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    |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
    • one year ago
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    |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
    • one year ago
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  46. UsukiDoll
    • one year ago
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    yeah what this guy wrote ^

  47. UsukiDoll
    • one year ago
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    because graphing manually is a pain. I think I overshot part b. oh well .

  48. UsukiDoll
    • one year ago
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    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
    • one year ago
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    @andrea0529 overshot part b. it was just asking the point of intersection with is (2,7) .

  50. anonymous
    • one year ago
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    Okay I get it know I mostly needed help with part a. I've got part b. Thank you so much.☺️

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