Home › AP EAMCET › Mathematics › Quadratic Equation › The equation x² − 4x + k = 0 has a double root w…
The equation x² − 4x + k = 0 has a double root when k equals
A8
B16
C4
D2
Answer & Solution
Correct answer: C. 4
Setting the discriminant 16 − 4k to zero gives k = 4, and the root is x = 2.
Related questions
For x² − 6x + 5 = 0 the numerical value of |α − β| isWhich is a factorisation of 6x² + x − 2?Factoring x² + 7x + 12 = 0 by inspection gives rootsCircle, ellipse, parabola and hyperbola equations are quadratic inProblems solvable by quadratic equations were known as early asThe word quadratic comes from a Latin word meaningThe reduced form of 2x² + 6x + 4 = 0 isDividing a quadratic by a gives a reduced form with leading coefficient