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Please help!(Vieta's Formulas) Let , , and be solutions to the equation . Find .Please include an explanation as well :)​

Answer»

SOLUTION :-

comparing 2x³ - 3x² + 4x - 1 = 0 with ax³ + bx² + cx + d = 0 we get,

  • a = 2
  • b = (-3)
  • c = 4
  • d = (-1)

since ROOTS are r, s and t ,

  • r + s + t = (-b/a) = -(-3/2) = 3/2
  • rs + st + rt = c/a = 4/2 = 2
  • rst = - d/a = -(-1)/2 = (1/2) .

we know that,

  • (a + b + c)² = a² + b² + c² + 2(ab + BC + ca)

then,

→ (r + s + t)² = r² + s² + t² + 2(rs + st + rt)

→ r² + s² + t² = (r + s + t)² - 2(rs + st + rt)

putting all values we get,

→ r² + s² + t² = (3/2)² - 2(2)

→ r² + s² + t² = (9/4) - 4

→ r² + s² + t² = (9 - 16)/4

→ r² + s² + t² = (-7/4) (Ans.)



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