Book: RS Aggarwal - Mathematics
Chapter: 10. Quadratic Equations
Subject: Maths - Class 10th
Q. No. 17 of Exercise 10A
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17
Solve each of the following quadratic equations:
15x2 - 28 = x
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 = 15 ; b = -1; c = -28
= 15. - 28 = - 420
And either of their sum or difference = b
= - 1
Thus the two terms are - 21 and 20
Difference = - 21 + 20 = - 1
Product = - 21.20 = - 420
3x(5x-7) + 4(5x-7) = 0
(5x-7)(3x + 4) = 0
(5x-7) = 0 or (3x + 4) = 0
x = 7/5 or x = (-4)/3
Roots of equation are 7/5, - 4/3
