# Use suitable identities to find the following products :- (3x + 4) (3x – 5) - Mathematics

Use suitable identities to find the following products :- (3x + 4) (3x – 5)

#### Solution

(3x + 4) (3x – 5) = 9(x+4/3)(x-5/3)

By using the identity (x + a)(x + b) = x2 + (a + b)x ab,

9(x+4/3)(x-5/3) = 9[x^2+(4/3-5/3)x+(4/3)(-5/3)]

= 9[x^2-1/3x-20/9]

= 9x^2-3x-20

Concept: Algebraic Identities
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#### APPEARS IN

NCERT Class 9 Maths
Chapter 2 Polynomials
Exercise 2.5 | Q 1.3 | Page 48