A Nice Algebra Problem | Math Olympiad | Equation

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  • Опубліковано 3 лют 2025

КОМЕНТАРІ • 34

  • @quinty.support
    @quinty.support 3 місяці тому +1

    a + b = ab = a/b
    (•°•) a + b = ab
    ab = a/b
    a + b = a/b
    By the equation: a + b = a/b
    Multiply both sides by b.....
    b(a + b) = b • a/b
    => ab + b² = a - (1)
    Substitute the value of a by (1) in the other equation:
    a + b = ab
    => (ab + b²) + b = ab
    => ab + b² + b - ab = 0 [Cancel → ab from both sides]
    => b² + b = 0
    => b(b + 1) = 0
    So either.....
    b = 0 or b + 1 = 0
    since b is in the denominator of (a/b) it is a non zero so first case → [rejected]
    b + 1 = 0
    => b = -1
    When b = -1, a + b = ab
    => a - 1 = -a
    [Add → +a on both sides of LHS and RHS]
    => a - 1 + a = 0
    => 2a - 1 = 0
    => 2a = 1
    => a = 1/2
    Verifying this value:
    a = 1/2, b = -1
    a + b = ab
    1/2 - 1 = 1/2
    => 1/2 = 1/2 [Verified]
    Since all the equations are same and equal... verification in one is true for all....
    hence, a = 1/2 ; b = -1 is the solution that satisfies all equation...

    • @SALogics
      @SALogics  3 місяці тому +1

      Very nice! ❤

  • @davidcawthorne7115
    @davidcawthorne7115 2 місяці тому +1

    Just note ab=a/b therefore b=1/b therefore b squared =1 therefore b =+ or-1. If +1 then a+1=a so we discard +1 And so a= -1 and as a+b = a/b then a-1 = -a/1 Therefore 2a=1 and so a=1/2. Job done. Well once you stick the values in all 3 equations as a check.

    • @SALogics
      @SALogics  2 місяці тому +1

      Very nice! ❤

  • @trojanleo123
    @trojanleo123 3 місяці тому +4

    a = 1/2 ; b = -1

    • @SALogics
      @SALogics  3 місяці тому +1

      Yes, you are right! ❤

  • @user-sr5lw3bv9
    @user-sr5lw3bv9 2 місяці тому +1

    a=ab-b and a=ab^2 or b=±1
    But b=1 is wrong in a+b=ab because 1=0 is wrong.
    So b=-1
    a-1=-a
    2a=1
    a=0,5

    • @SALogics
      @SALogics  2 місяці тому +2

      Very nice! ❤

  • @shmuelzehavi4940
    @shmuelzehavi4940 3 місяці тому +3

    You've already showed that a=0 implies: b=0, which is impossible at first place. This fact excludes the solution: a=0. Therefore, it is logically pointless to put afterwards the value : a=0 into the other equations.

    • @SALogics
      @SALogics  3 місяці тому +1

      a=0 is not the solution! ❤

  • @tingsuji8331
    @tingsuji8331 3 місяці тому +1

    Very interesting 😊

    • @SALogics
      @SALogics  3 місяці тому +1

      Glad you think so! ❤

  • @key_board_x
    @key_board_x 3 місяці тому +1

    ab = a/b → where: b ≠ 0
    ab - (a/b) = 0
    (ab² - a)/b = 0
    ab² - a = 0
    a.(b² - 1) = 0
    First case: a = 0
    Given: a + b = a/b → when: a = 0
    0 + b = 0/b
    b = 0 → rejected because the condition: b ≠ 0
    Second case: (b² - 1) = 0
    b² = 1
    b = ± 1
    First solution: b = 1
    Given: a + b = a/b → when: b = 1
    a + 1 = a/1
    a + 1 = a
    1 = 0 ← false, solution to be rejected
    Second solution: b = - 1
    Given: a + b = a/b → where: b = - 1
    a - 1 = a/- 1
    a - 1 = - a
    2a = 1
    a = 1/2
    Unique solution (a ; b) → (1/2 ; - 1)

    • @SALogics
      @SALogics  3 місяці тому +1

      Very nice! ❤

  • @9허공
    @9허공 3 місяці тому +1

    let a/b = k => a = bk, ab = k => kb^2 = k =>k(b^2 - 1) = 0 => k = 0 or b = 1, -1
    (case k = 0) => a = 0, b = 0 => since b ≠ 0, no solution.
    (case b = 1) => a + 1 = a = a/1 => no solution.
    (case b = -1) => a - 1 = -a = a/-1 => a =1/2 Answer (a,b) = (1/2, -1)

    • @SALogics
      @SALogics  3 місяці тому +2

      Very nice! ❤

  • @فیروزاهنگری
    @فیروزاهنگری 2 місяці тому +1

    ab=a/b , ab^2=a , a(b^2-1)=0
    a=0 or b=1. or b=-1
    case1 a=0. a+b=ab , 0+b=0×b
    b=0 unacceptable
    case2. b=1. a+1=a , 1=0 impossible case3. b=-1
    a-1=-a. , a=1/2. acceptable

    • @SALogics
      @SALogics  2 місяці тому

      Very nice! ❤

  • @zawatsky
    @zawatsky Місяць тому

    a+b=a/b⇒ab+b²=a. a+b=ab⇒ -a- +b+b²= -a- . b²+b=0. b(b+1)=0 при b≠0. b+1=0⇒b=-1. a-1=-a⇒2a=1⇒a=½. Проверка: ½-1=-½. ½×(1-)=-½. ½÷(-1)=-½.

    • @SALogics
      @SALogics  Місяць тому +1

      Very nice! ❤

  • @MananArhamOP
    @MananArhamOP 3 місяці тому +1

    Big fan

    • @SALogics
      @SALogics  3 місяці тому +1

      Thank you so much! ❤

  • @Misha-g3b
    @Misha-g3b 2 місяці тому +1

    a=0.5 , b=-1.

    • @SALogics
      @SALogics  2 місяці тому +2

      Very nice! ❤

    • @Misha-g3b
      @Misha-g3b 2 місяці тому

      @@SALogics Thank You!

  • @mkadx2136
    @mkadx2136 3 місяці тому +1

    تستطيع حلها عن طريق التمثيل الباتي في اقل من دقيقة

    • @SALogics
      @SALogics  3 місяці тому +2

      لطيف جدًا❤

  • @clayton97330
    @clayton97330 3 місяці тому +3

    As soon as a case is disproven by one equation, you don't need to check the other equations.

    • @SALogics
      @SALogics  3 місяці тому +1

      Very nice! ❤

  • @AvnishSwar
    @AvnishSwar Місяць тому +1

    I have a doubt in the solution why can't
    "a" tend to postive infinity
    And b belongs to (0+,+infinity)
    Such that ab also tends to postive infinity and a/b also tends to postive infinity

    • @SALogics
      @SALogics  Місяць тому +1

      The Solution are verified in the end! ❤

  • @SijinaV-m9q
    @SijinaV-m9q 2 місяці тому +1

    Sir another answer is
    a) (√5 -1)/2
    b) 1
    •(√5-1)/2+1 = √5-1/2
    •(√5-1)/2 ×1 = "
    •(√5-1/2)÷1 = "

    • @SALogics
      @SALogics  2 місяці тому +1

      Very nice! ❤

    • @lawrencebates8172
      @lawrencebates8172 2 місяці тому

      Err, doesn't (√5-1)/2 + 1 = (√5)/2 + 1/2, while (√5-1)/2 ×1 = (√5-1/2)÷1 = (√5)/2 - 1/2 ?