2018 Question Paper Solution | Question 1

This is an easy 1-mark question from the chapter Quadratic Equations. Concept tested: Significance of the root of a quadratic equation.

Question 1: If x = 3 is one root of the quadratic equation x² – 2kx – 6 = 0, then find the value of k.

Video Explanation

Explanatory Answer | Q1 2018 Board Paper

x = 3 is one root of x² - 2kx - 6 = 0
Because 3 is one of the roots of the equation, substituting x= 3 will satisfy the equation.
3² - 2 × k × 3 - 6 = 0
9 - 6k - 6 = 0
6k = 3 or k = \\frac{3}{6}) = \\frac{1}{2})