The coefficient of x in the expansion of (x + 3)³ is
a. 1
b. 9
c. 18
d. 27

Solution:

It is given that

(x + 3)³

Using the algebraic identity (a + b)³ = a³ + b³ + 3ab (a + b)

(x + 3)³ = x³ + 3³ + 3x (3) (x + 3)

By further simplification

(x + 3)³ = x³ + 27 + 9x (x + 3)

So we get

(x + 3)³ = x³ + 27 + 9x² + 27x

Therefore, the coefficient of x is 27.

✦ Try This: The coefficient of x in the expansion of (x + 2)³ is

☛ Also Check: NCERT Solutions for Class 9 Maths Chapter 2

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NCERT Exemplar Class 9 Maths Exercise 2.1 Problem 18

The coefficient of x in the expansion of (x + 3)³ is a. 1, b. 9, c. 18, d. 27

Summary:

A coefficient refers to a number or quantity placed with a variable. The coefficient of x in the expansion of (x + 3)³ is 27

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