Math Problem Statement

answers

Mrs. Jones gave her students the ordered pair (12, -4) and told them y varies directly with x. What is the constant of variation when y is a function of x, and what is the value of x when y = -6?

Solution

Let's solve the problem step by step:

The problem states that yy varies directly with xx. This means that y=kxy = kx, where kk is the constant of variation.

Step 1: Find the constant of variation (kk).

We are given the ordered pair (12,4)(12, -4). Plugging this into the direct variation equation:

4=k12-4 = k \cdot 12

To solve for kk:

k=412=13k = \frac{-4}{12} = -\frac{1}{3}

So, the constant of variation is k=13k = -\frac{1}{3}.

Step 2: Find the value of xx when y=6y = -6.

Using the equation y=kxy = kx, substitute y=6y = -6 and k=13k = -\frac{1}{3}:

6=13x-6 = -\frac{1}{3} \cdot x

Multiply both sides by 3-3 to solve for xx:

x=18x = 18

Final answers:

  • The constant of variation is 13-\frac{1}{3} (or -⅓).
  • The value of xx when y=6y = -6 is 1818.

Now, using the available choices in the image:

  • The constant of variation is 13-\frac{1}{3}.
  • The value of xx is 1818.

Would you like more details on this? Here are five related questions to expand your understanding:

  1. How do you determine if a relationship shows direct variation?
  2. What would change if yy varied inversely with xx instead of directly?
  3. Can a constant of variation ever be zero in direct variation?
  4. How do we interpret the graph of a direct variation relationship?
  5. How would you solve for kk if multiple ordered pairs are given?

Tip: In a direct variation, as one variable increases or decreases, the other does so proportionally. The constant kk helps establish this relationship.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Direct Variation
Linear Relationships

Formulas

y = kx

Theorems

Direct Variation

Suitable Grade Level

Grade 8-9