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The Sum of the Squares of Three Consecutive Natural Numbers as 149. Find the Numbers - Mathematics

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Question

The sum of the squares of three consecutive natural numbers as 149. Find the numbers

Solution

Let the numbers be x, x + 1 and x + 2 according to the given hypothesis.

๐‘ฅ2 + (๐‘ฅ + 1)2 + (๐‘ฅ + 2)2 = 149

⇒ ๐‘ฅ2 + ๐‘ฅ2 + 1 + 2๐‘ฅ + ๐‘ฅ2 + 4 + 4๐‘ฅ = 149

⇒ 3๐‘ฅ2 + 6๐‘ฅ + 5 - 149 = 0

⇒ 3๐‘ฅ2 + ๐‘ฅ - 144 = 0

⇒ ๐‘ฅ2 + 2๐‘ฅ - 48 = 0

⇒ ๐‘ฅ(๐‘ฅ + 8) - 6(๐‘ฅ + 8) = 0

⇒ (๐‘ฅ + 8)(๐‘ฅ - 6) = 0

⇒ x = -8 or x = 6

Considering the positive value of x

๐‘ฅ = 6, ๐‘ฅ + 1 = 7 ๐‘Ž๐‘›๐‘‘ ๐‘ฅ + 2 = 8

∴ The three consecutive numbers are 6, 7, 8.

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Chapter 4: Quadratic Equations - Exercise 4.7 [Page 52]

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RD Sharma Mathematics [English] Class 10
Chapter 4 Quadratic Equations
Exercise 4.7 | Q 18 | Page 52
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