Book: RS Aggarwal - Mathematics
Chapter: 10. Quadratic Equations
Subject: Maths - Class 10th
Q. No. 2 of Exercise 10C
Listen NCERT Audio Books to boost your productivity and retention power by 2X.
2
Find the roots of each of the following equations, if they exist, by applying the quadratic formula:
x2 – 4x – 1 = 0
Given: x2 – 4x – 1 = 0
Comparing with standard quadratic equation ax2 + bx + c = 0
a = 1, b = – 4, c = – 1
Discriminant D = b2 – 4ac
= (– 4)2 – 4.1. – 1
= 16 + 4 = 20 > 0
Hence the roots of equation are real.
Roots 
are given by
Hence the roots of equation are 
