éxample, 257 = 16² + 1. Exhibit five more primes of this type. 10. If p #5 is an odd prime, prove that either p² -1 or p2+ 1 is divisible by 10. 11. Another unproven conjecture is that there are an infinitude of primes that are 1 less than a power of 2, such as 3 = 22- 1. (a) Find four more of these primes. (b) If p = 24 - 1 is prime, show that k is an odd integer, except when k = 2. [Hint: 314"-1 for all n> 1.] 12. Find the prime factorization of the integers 1234, 10140, and 36000. 13. If n > 1 is an integer not of the form 6k + 3, prove that n"+2" is composite. [Hint: Show that either 2 or 3 divides n2+2".]
Percentage
A percentage is a number indicated as a fraction of 100. It is a dimensionless number often expressed using the symbol %.
Algebraic Expressions
In mathematics, an algebraic expression consists of constant(s), variable(s), and mathematical operators. It is made up of terms.
Numbers
Numbers are some measures used for counting. They can be compared one with another to know its position in the number line and determine which one is greater or lesser than the other.
Subtraction
Before we begin to understand the subtraction of algebraic expressions, we need to list out a few things that form the basis of algebra.
Addition
Before we begin to understand the addition of algebraic expressions, we need to list out a few things that form the basis of algebra.
![- bs) = (/2a)r +(/2b)s
This representation of 2 leads us to conclude that 2 is an integer, an obvious
= 2br + as
with
impossibility.
PROBLEMS 3.1
1. It has been conjectured that there are infinitely many primes of the form n² – 2. Exhibit
five such primes.
2. Give an example to show that the following conjecture is not true: Every positive integer
can be written in the form p +a², where p is either a prime or 1, and a > 0.
3. Prove each of the assertions below:
(a) Any prime of the form 3n +1 is also of the form 6m + 1.
(b) Each integer of the form 3n + 2 has a prime factor of this form.
(c) The only prime of the form n³ – 1 is 7.
[Hint: Write n³ – 1 as (n – 1)(n² + n + 1).]
(d) The only prime p for which 3p+ 1 is a perfect square isp=5.
(e) The only prime of the form n² – 4 is 5.
4. If p 2 5 is a prime number, show that p2 +2 is composite.
[Hint: p takes one of the forms 6k + 1 or 6k + 5.]
5. (a) Given that p is a prime and p|a", prove that p" | a".
(b) If gcd(a, b) = p, a prime, what are the possible values of gcd(a², b²), gcd(a², b) and
gcd(a', b?)?
6. Establish each of the following statements:
(a) Every integer of the form n* +4, with n > 1, is composite.
[Hint: Write n* + 4 as a product of two quadratic factors.]
(b) If n > 4 is composite, then n divides (n – 1)!.
(c) Any integer of the form 8" + 1, where n > 1, is composite.
[Hint: 2" + 1|23n + 1.]
(d) Each integer n > 11 can be written as the sum of two composite numbers.
[Hint: If n is even, say n = 2k, then n – 6 = 2(k – 3); for n odd, consider the integer
n - 9.]
ther
on
of
7. Find all prime numbers that divide 50!.
8. If p >q > 5 and p and q are both primes, prove that 24 | p2 – q°.
9. (a) An unanswered question is whether there are infinitely many primes that are 1 more
than a power of 2, such as 5 = 22 + 1. Find two more of these primes.
(b) A more general conjecture is that there exist infinitely many primes of the form
n2 + 1; for example, 257 = 162 + 1. Exhibit five more primes of this type.
10. If p #5 is an odd prime, prove that either p² – 1 or p2 + 1 is divisible by 10.
11. Another unproven conjecture is that there are an infinitude of primes that are 1 less than
a power of 2, such as 3 = 22 – 1.
(a) Find four more of these primes.
(b) If p = 2k - 1 is prime, show that k is an odd integer, except when k = 2.
[Hint: 3|4"-1 for all n > 1.]
12. Find the prime factorization of the integers 1234, 10140, and 36000.
13. If n > 1 is an integer not of the form 6k + 3, prove that n'+2" is composite.
[Hint: Show that either 2 or 3 divides n2+ 2".]](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F7dbb4ae4-0d65-4baa-9481-63f79be91eca%2F512b67e7-2cc1-4808-8bbe-a289a1b86139%2Fpw9wr7l_processed.jpeg&w=3840&q=75)
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