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JessNicole

  • 3 years ago

x+y=4 2x-y=5 What is the solution to this system?

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  1. gerryliyana
    • 3 years ago
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    use elimination method

  2. Mr.Me
    • 3 years ago
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    add down using elimination method

  3. Rosh007
    • 3 years ago
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    add solve for x then solve for y I think it will be easier

  4. gerryliyana
    • 3 years ago
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    multiply both side of x+y=4 by 5 and multiply both side of 2x-y=5 by 4

  5. Rosh007
    • 3 years ago
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    I think adding two equation will give you in x terms only... no ned to go in a roundabout way

  6. JessNicole
    • 3 years ago
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    Thank you SO MUCH! all of you @gerryliyana @Rosh007 @Mr.Me I appreciate 100% :p

  7. gerryliyana
    • 3 years ago
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    welcome :)

  8. Rosh007
    • 3 years ago
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    welcome..so u got it... O glad..

  9. JessNicole
    • 3 years ago
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    Is the answer suppose to be a decimal tho??

  10. JessNicole
    • 3 years ago
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    because i got -0.3333333333.. etc.

  11. gerryliyana
    • 3 years ago
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    what did u get it??

  12. gerryliyana
    • 3 years ago
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    show in -1/3

  13. JessNicole
    • 3 years ago
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    by using the elimination method ... Oh okay @gerryliyana then plug that in to x in x+y=4 ?

  14. Rosh007
    • 3 years ago
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    yes... first you nd to eliminate one variable... sinc there are two equations and two unknowns.. it would is possible... but you won't get -0.3333.. in this case

  15. gerryliyana
    • 3 years ago
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    yes

  16. Rosh007
    • 3 years ago
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    NO!!! you have two use the equations which are available to you

  17. JessNicole
    • 3 years ago
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    What would it be @Rosh007 because thats what i got, am i doing it wrong then??

  18. gerryliyana
    • 3 years ago
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    ur right @JessNicole

  19. jazy
    • 3 years ago
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    Try using substitution and see if you got the same as me. (:

  20. Rosh007
    • 3 years ago
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    @jazy you made a mistake here Solve for x in the first equation. x + y = 4 Subtract y. x = 4 - y Substitute the value of x into the second equation. Solve for y. 2(4 - y) = 5 ----- mistake

  21. gerryliyana
    • 3 years ago
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    be careful @jazy 2(4 - y) = 5 ???? the right is 2(4 - y) - y= 5

  22. jazy
    • 3 years ago
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    Oh okay now I see.

  23. JessNicole
    • 3 years ago
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    @jazy THANK YOU!!! it makes sence but @Rosh007 how is it a mistake?

  24. gerryliyana
    • 3 years ago
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    be careful @jazy the mistake at 2(4 - y) = 5 ???? the right is 2(4 - y) - y= 5

  25. Rosh007
    • 3 years ago
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    @JessNicole please look gerryliyana's reply

  26. JessNicole
    • 3 years ago
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    Ohh okayy, i see now soo, it'd be Distribute 8-y=5?? @Rosh007 and @jazy ??

  27. Rosh007
    • 3 years ago
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    jazzy missed one y there

  28. JessNicole
    • 3 years ago
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    @gerryliyana Thank youuuu!!:) for catching that mistake, i fixed it on my paper!

  29. gerryliyana
    • 3 years ago
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    no

  30. jazy
    • 3 years ago
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    I prefer substitution. x + y = 4 2x - y = 5 Solve for x in the first equation. x + y = 4 Subtract y. x = 4 - y Substitute the value of x into the second equation. Solve for y. 2(4 - y) - y = 5 Distribute. 8 - 2y - y= 5 Subtract 8. -2y - y = -3 -3y = -3 Divide both sides by -3. y = 1 Now plug in the value of y(1) into any equation to solve for x. x + y = 4 x + 1 = 4 Subtract 1 x = 3 ---------------------------------- So x = 3 and y = 1

  31. JessNicole
    • 3 years ago
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    @gerryliyana What would it be then?

  32. gerryliyana
    • 3 years ago
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    2(4 - y) - y= 5 8 - 3y = 5

  33. gerryliyana
    • 3 years ago
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    2(4 - y) - y= 5 8 - 3y = 5

  34. jazy
    • 3 years ago
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    Thank you catching that mistake! (:

  35. jazy
    • 3 years ago
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    It should be right now!

  36. Rosh007
    • 3 years ago
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    yes you got it jazzy.. but a very simpl method is there

  37. gerryliyana
    • 3 years ago
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    @JessNicole 2(4 - y) - y= 5 8 - 3y = 5

  38. JessNicole
    • 3 years ago
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    @jazy @Rosh007 @gerryliyana THANK YOUUUUUUUUU!! SO MUCH EVERYONE!!:D .. I'd give all of you guys each a medal if i could!!

  39. Rosh007
    • 3 years ago
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    sice answer is already wrote here( which I don't like to do write directly) it is for you to know that there is a simple method than this

  40. Rosh007
    • 3 years ago
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    @jazy you are welcome

  41. gerryliyana
    • 3 years ago
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    @JessNicole ur welcome..., happy to help u :)

  42. JessNicole
    • 3 years ago
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    @Rosh007 There's an easier way ? cause you can teach it to me ..this stuff is hard for me, i'm always confused.

  43. Rosh007
    • 3 years ago
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    actually it is derivd from the method mentioned here.. It is actually a special case of this method.. it is applicabl here since in one equation +y and in other equation -y is there actually the problem is simple x+y=4 2x-y=5 |dw:1353003234368:dw| so when we add both equation (LHS with LHS and RHS with RHS) you get 3x =9 which can be simplified quickly and reach the answer fast

  44. Rosh007
    • 3 years ago
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    You understood?

  45. Rosh007
    • 3 years ago
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    actually the problem is simple x+y=4 2x-y=5 add x+y+2x-y = 5+4 3x+0 = 9 3x =9 if you substitute the value of x in equn 1 you get th value of y....

  46. JessNicole
    • 3 years ago
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    @Rosh007, yess! i understood perfectly. It is much simpler!..Thank you very much. I really appreciate it.!:)

  47. Rosh007
    • 3 years ago
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    Welcome...But remember it is a special case ;) all the best

  48. JessNicole
    • 3 years ago
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    Ha ha okay, thank youagain !:p

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