Book: RS Aggarwal - Mathematics
Chapter: 10. Quadratic Equations
Subject: Maths - Class 10th
Q. No. 16 of Exercise 10B
Listen NCERT Audio Books to boost your productivity and retention power by 2X.
16
By using the method of completing the square, show that the equation 2x2 + x + 4 = 0 has no real roots.
2x2 + x + 4 = 0
4x2 + 2x + 8 = 0 (multiplying both sides by 2)
4x2 + 2x = - 8
[Adding 
on both sides]
using a2 + 2ab + b2 = (a + b)2
But 
cannot be negative for any real value of x
So there is no real value of x satisfying the given equation.
Hence the given equation has no real roots.
