KVPY2015MathematicsQuadratic Equation
Two distinct polynomial f ( x ) and g ( x ) are defined as follows: f(x)=x²+a x+2 ; g(x)=x²+2 x+a If the equation f(x)=0 and g(x)=0 have a common root then the sum of the roots of the equation f(x)+g(x)=0 is
Options
- A- 1 2
- B0
- C1 2
- D1
Correct answer
C. 1 2
Step-by-step solution
array l f(x)=x²+a x+2 g(x)=x²+2 x+a array Here a common Roat then | array ll 1 & a 1 & 2 array | | array ll a & 2 2 & a array |= | array cc 2 & 1 a & 1 array |² array l = a=2,-3 f(x)+g(x)=2 x²+(a+2) x+a+2 array Sum of roots = -( a +2) 2 if a =-3 then sum = 1 2