Math Problem Statement

For each part below, fill in the blank with the smallest whole number that makes the statement true. (a) -7 ≡ □ (mod 6) (b) 10 - 17 ≡ □ (mod 9)

Solution

Let's solve each part of the problem by finding the smallest whole number that satisfies each congruence.

Part (a)

We need to find the smallest whole number xx such that: 7x(mod6)-7 \equiv x \pmod{6}

To solve this, we need to find the remainder when 7-7 is divided by 66. We can add 66 repeatedly until the result is non-negative:

7+6=1-7 + 6 = -1

1+6=5-1 + 6 = 5

So, 75(mod6)-7 \equiv 5 \pmod{6}. The smallest whole number for xx that makes the statement true is 5.

Part (b)

We need to find the smallest whole number yy such that: 1017y(mod9)10 - 17 \equiv y \pmod{9}

First, compute 1017=710 - 17 = -7. Now, we need to find the remainder when 7-7 is divided by 99. Similar to part (a), we add 99 repeatedly until the result is non-negative:

7+9=2-7 + 9 = 2

So, 72(mod9)-7 \equiv 2 \pmod{9}. The smallest whole number for yy that makes the statement true is 2.

Final Answers:

  • (a) x=5x = 5
  • (b) y=2y = 2

Would you like more details or have any questions?

Here are 5 related questions to explore:

  1. What is the general method for solving linear congruences?
  2. How can we solve a system of congruences using the Chinese Remainder Theorem?
  3. What are some real-world applications of modular arithmetic?
  4. How does modular arithmetic apply to cryptography?
  5. How can we find the multiplicative inverse in modular arithmetic?

Tip: When working with modular arithmetic, always remember that adding or subtracting multiples of the modulus does not change the congruence.

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Math Problem Analysis

Mathematical Concepts

Modular Arithmetic
Congruences
Number Theory

Formulas

x ≡ y (mod n)
Remainder when dividing a number by n

Theorems

Modular Arithmetic Properties

Suitable Grade Level

Grades 9-12