📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!

  • google app store apple app store

    • Question

      If a + b + c = 18, and a ³ + b ³ + c ³ - 3abc = 54, hen

      find the value of 5(ab + bc + ca).
      A 320 Correct Answer Incorrect Answer
      B 250 Correct Answer Incorrect Answer
      C 535 Correct Answer Incorrect Answer
      D 328 Correct Answer Incorrect Answer

      Solution

      ATQ,

      Given, a + b + c = 18

      We know that,
      Image
      So, 54 = 18 × (18²−3(ab + bc + ca))

      54 = 18 × (324 − 3(ab + bc + ca))

      Divide both sides by 18:

      3 = 324 −3(ab + bc + ca)

      3(ab + bc + ca) = 321

      ab + bc + ca =107

      So, required value = 5 × 107= 535

      Practice Next

      Relevant for Exams:

      ask-question