Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
AP EAMCET201920 Apr 2019Evening ShiftMathematicsQuadratic EquationActual

If , , are the roots of the equation x^3-a x^2+b x-c=0 , then ^2( + )=

Options

  1. Aa b-3 c
  2. Ba b-3 c c
  3. Cb^2-2 a c c^2
  4. Da^2-2 b c^2

Correct answer

A. a b-3 c

Step-by-step solution

If , , are the roots of the equation. x^3-a x^2+b x-c=0 Then, + + =a, + + =b and =c . Now, ^2( + )= ^2(a- ) [as + + =a] aligned & =a ^2- ^3 & =a [( + + )^2-2( + + ) ]-[( + + ) & . ( ^2+ ^2+ ^2- - - )+3 ] & =a [( + + )^2-2( + + ) ]-( + + ) & ( + + )^2-3( + + )+3 ] & =a [a^2-2 b ]- [a a^2-3 b +3 c ] & =a^3-2 a b-a^3+3 a b-3 c=a b-3 c aligned Hence, option (a) is correct.

Practice Quadratic Equation on Quantrex Academy →

More from Quadratic Equation

If is the common root of the quadratic equations x^2-5 x+4 a=0 , x^2-2 a x-8=0 , where a R , then the value of ^4- ^3+68 is 2025If , are the roots of x^2-5 x-6 =0 and , are the roots of x^2-5 x-6 =0 , then + + + = 2025If , , are the roots of the equation x ^3+ px ^2+ qx + r =0 , then ( + )( + )( + )= 2025Let f(x)=x^2+2 b x+2 c^2 and g(x)=-x^2-2 c x+b^2, x R . If b and c are nonzero real numbers such that f(x)> g(x) , then | c b | lies in the interval 2025If x ^2-4 ax +5+ a >0 for all x R whenever a ( , ) , then 4 + = 2025If , , are the roots of the equation x^3-12 x^2+k x-18=0 and one of them is thrice the sum of the other two roots, then ^2+ ^2+ ^2-k= 2025The polynomial equation of degree 5 whose roots are the roots of the equation x^5-3 x^4-x^3+11 x^2-12 x+4=0 each increased by 2, is 2025If the difference of the roots of the equation x^2-7 x+10=0 is same as the difference of the roots of the equation x ^2-17 x + k =0 , then a divisor of k is 2025 Full Quadratic Equation list All AP EAMCET PYQs