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Question

The greatest prime factor of $(3^{199} – 3^{196})$ is

The correct answer is
13

Factorization of Expression

We need to find the greatest prime factor of the expression $(3^{199} – 3^{196})$. First, factor out the common term, which is the lowest power of 3, $3^{196}$.

$3^{199} – 3^{196} = 3^{196} (3^{199-196} – 1)$

Simplifying the Expression

Now, simplify the term inside the parenthesis:

$3^{196} (3^3 – 1)$

Calculate $3^3$:

$3^3 = 3 \times 3 \times 3 = 27$

Substitute this back into the expression:

$3^{196} (27 – 1) = 3^{196} \times 26$

Prime Factorization

To find the greatest prime factor, we determine the prime factors of the simplified expression $3^{196} \times 26$.

  • The prime factors of $3^{196}$ consist only of the prime number 3.
  • Find the prime factors of 26: $26 = 2 \times 13$. Both 2 and 13 are prime numbers.

The prime factors of the entire expression $(3^{199} – 3^{196})$ are therefore 3, 2, and 13.

Greatest Prime Factor Identification

Comparing the prime factors {2, 3, 13}, the largest number is 13.

Thus, the greatest prime factor of $(3^{199} – 3^{196})$ is 13.

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Important Questions from Integers

  1. The average of eleven consecutive positive integers is d. If the last two numbers are excluded, by how much will the average increase or decrease?
  2. The numerator of fraction is 3 more than the denominator. When 5 is added to the numerator and 2 is subtracted from the denominator, the fraction becomes 8/3, When the original fraction is divided by \(5 \frac{1}{2}\) , the fraction so obtained is:

  3. The sum of a non - zero number and twenty times its reciprocal is 9. What is the number?

  4. If \(\frac{{45}}{{53}} = \frac{1}{{a + \frac{1}{{b + \frac{1}{{c - \frac{2}{5}}}}}}},\)  where a, b and c are positive integers, then what is the value of (4a - b + 3c)

  5. The denominator of a fraction is 4 more than the double of its numerator. When 3 is added to the numerator and 3 is subtracted from denominator the fraction becomes 2/3. Then find the difference between denominator and numerator of the original fration. 

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