# Thread: Rate of Change of Slope

1. ## Rate of Change of Slope

For dogs that are two or more years old, the equation $5x-y+12=0$ compares dog year to human years. In the equation, $x$ represents the acutal age of a dog, and $y$ in the age of the dog in human years.

What rate of change does the slope represent?

Testbook answer: 5 dog years for every human year.

I don't why though? Can anyone help me out? Thanks.

2. The rate of change in a linear function like you have is $m$ where $y=mx+c$

$5x-y+12=0 \implies y=5x+12$

Can you see how $m=5$ in your case?

3. Originally Posted by pickslides
The rate of change in a linear function like you have is $m$ where $y=mx+c$

$5x-y+12=0 \implies y=5x+12$

Can you see how $m=5$ in your case?
I know $m = 5$

But wouldn't that be 5 up 1 across on the graph? It said $x$ is the actual dog age and $y$ is dog's age in human years. Doesn't that mean it's 5 human years for every dog year?

4. Originally Posted by larry21
I know $m = 5$

But wouldn't that be 5 up 1 across on the graph? It said $x$ is the actual dog age and $y$ is dog's age in human years. Doesn't that mean it's 5 human years for every dog year?
x is human years and y is dog years.

Otherwise, a dog that is 4 dog years old would be 32 human years old, which makes no sense.