A direct variation function contains the points [tex]$(-8,-6)$[/tex] and [tex]$(12,9)$[/tex]. Which equation represents the function?

A. [tex]$y=-\frac{4}{3} x$[/tex]
B. [tex][tex]$y=-\frac{3}{4} x$[/tex][/tex]
C. [tex]$y=\frac{3}{4} x$[/tex]
D. [tex]$y=\frac{4}{3} x$[/tex]



Answer :

To determine which equation represents the direct variation function containing the points [tex]\((-8, -6)\)[/tex] and [tex]\( (12, 9)\)[/tex], follow these steps:

1. Identify the coordinates of the given points:
- Point 1: [tex]\((-8, -6)\)[/tex]
- Point 2: [tex]\( (12, 9)\)[/tex]

2. Use the slope formula to calculate the slope [tex]\( k \)[/tex] of the line passing through these points:
[tex]\[ k = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]
Substituting the given points [tex]\((x_1, y_1) = (-8, -6)\)[/tex] and [tex]\((x_2, y_2) = (12, 9)\)[/tex]:
[tex]\[ k = \frac{9 - (-6)}{12 - (-8)} \][/tex]

3. Simplify the expression to find the slope [tex]\( k \)[/tex]:
[tex]\[ k = \frac{9 + 6}{12 + 8} = \frac{15}{20} = \frac{3}{4} \][/tex]
The slope [tex]\( k \)[/tex] of the direct variation function is [tex]\(\frac{3}{4}\)[/tex].

4. Compare the calculated slope with the given equations:
- [tex]\( y = -\frac{4}{3} x \)[/tex]: Slope is [tex]\(-\frac{4}{3}\)[/tex]
- [tex]\( y = -\frac{3}{4} x \)[/tex]: Slope is [tex]\(-\frac{3}{4}\)[/tex]
- [tex]\( y = \frac{3}{4} x \)[/tex]: Slope is [tex]\(\frac{3}{4}\)[/tex]
- [tex]\( y = \frac{4}{3} x \)[/tex]: Slope is [tex]\(\frac{4}{3}\)[/tex]

5. Identify the equation that matches the calculated slope:
- The equation [tex]\( y = \frac{3}{4} x \)[/tex] has a slope of [tex]\(\frac{3}{4}\)[/tex].

Therefore, the equation representing the direct variation function that contains the points [tex]\((-8, -6)\)[/tex] and [tex]\( (12, 9)\)[/tex] is:
[tex]\[ y = \frac{3}{4} x \][/tex]