Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NDA2025MathematicsQuadratic EquationActual

If x^2 - x + 1 = 0 , then what is (x - 1 x )^2 + (x - 1 x )^4 + (x - 1 x )^8 equal to?

Options

  1. A81
  2. B85
  3. C87
  4. D90

Correct answer

C. 87

Step-by-step solution

Given x^2 - x + 1 = 0 Dividing the entire equation by x , we get: x - 1 + 1 x = 0 x + 1 x = 1 Using the algebraic identity (x - 1 x )^2 = (x + 1 x )^2 - 4 Substituting the value of x + 1 x : (x - 1 x )^2 = (1)^2 - 4 = -3 The given expression is (x - 1 x )^2 + (x - 1 x )^4 + (x - 1 x )^8 This can be written as (x - 1 x )^2 + ( (x - 1 x )^2 )^2 + ( (x - 1 x )^2 )^4 Substituting (x - 1 x )^2 = -3 into the expression: (-3) + (-3)^2 + (-3)^4 = -3 + 9 + 81 = 87 Answer: 87

Practice Quadratic Equation on Quantrex Academy →

More from Quadratic Equation

For a given k , what is the minimum value of x^2+kx+k^2 ? 2026If the highest degree coefficient is equal to 1 , then what is the total number of quadratic equations which are unchanged on squaring their roots ? 2026Let and be the roots of the quadratic equation x^2-2bx+c^2=0 where b , c are positive real numbers. Let A be the arithmetic mean of and ; and G be the geometric mean of and . What 2026Consider the following statements : I. x +x+1=0 has two irrational roots. II. 5 x -x-4=0 has two rational roots. Which of the statements given above is/are correct ? 2026For the following two (02) items: Let f(x) = ax^2 + bx + c be a quadratic polynomial such that f(1) = f(4) = 2 . Further, 2 is a root of f(x) = 0 . What is (a + b + c) equal to? 2025For the following two (02) items: Let and be the roots of the quadratic equation x^2 + ( _ 0.5 (a^2))x + ( _ 0.5 (a^2))^4 = 0 , where a^2 1 and _ 0.5 (a^2) > 0 . Further, ^2 = ( _ 2025For the following two (02) items: Let f(x) = ax^2 + bx + c be a quadratic polynomial such that f(1) = f(4) = 2 . Further, 2 is a root of f(x) = 0 . What is the other root of f(x) = 2025If one root of the equation x^2 - kx + k = 0 exceeds the other by 2 3 , then which one of the following is a value of k ? 2025 Full Quadratic Equation list All NDA PYQs