Book: RS Aggarwal - Mathematics
Chapter: 10. Quadratic Equations
Subject: Maths - Class 10th
Q. No. 53 of Exercise 10A
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53
Solve each of the following quadratic equations:
taking LCM
x + 4 = 2x2 + 3x cross multiplying
2x2 + 2x - 4 = 0 taking 2 common
x2 + x - 2 = 0
Using the splitting middle term - the middle term of the general equation 
is divided in two such values that:
Product = a.c
For the given equation a = 1 b = 1 c = - 2
= 1. - 2 = - 2
And either of their sum or difference = b
= 1
Thus the two terms are 2 and - 1
Difference = 2 - 1 = 1
Product = 2. - 1 = - 2
x2 + x - 2 = 0
x2 + 2x - x - 2 = 0
x(x + 2) - (x + 2) = 0
(x + 2) (x - 1) = 0
(x + 2) = 0 or (x - 1) = 0
x = - 2 or x = 1
Hence the roots of equation are - 2 or 1.
