Book: RS Aggarwal - Mathematics
Chapter: 10. Quadratic Equations
Subject: Maths - Class 10th
Q. No. 7 of Exercise 10C
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7
Find the roots of each of the following equations, if they exist, by applying the quadratic formula:
15x2 – 28 = x
Given: 15x2 – 28 = x
15x2 – x – 28 = 0
Comparing with standard quadratic equation ax2 + bx + c = 0
a = 15, b = – 1, c = – 28
Discriminant D = b2 – 4ac
= (– 1)2 – 4.15. – 28
= 1 + 1680 = 1681 > 0
Hence the roots of equation are real.
Roots 
are given by
Hence the roots of equation are 
