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Question
The coefficient of x in the expansion of (x + 3)3 is ______.
Options
1
9
18
27
Solution
The coefficient of x in the expansion of (x + 3)3 is 27.
Explanation:
Consider the expression:
(x + 3)3
Use the identity: (a + b)3 = a3 + b3 + 3ab(a + b)
(x + 3)3 = x3 + 33 + 3 × x × 3(x + 3)
= x3 + 27 + 9x2 + 27x
Since, the coefficient of x is 27.
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