Which function is increasing at the highest rate?

Hi! We can know which function has the highest rate of increase by looking at its slope. The function with the highest slope will have the highest rate (recall the definition of slope which is rise/run).

Let's ignore the first option since the function is clearly decreasing. For the second one, the slope would be 2. For the third one, we compute the slope below:



Lastly, we solve for the slope of the fourth option by using the points (8,0), and (0,-4):



Clearly, option 2 has the highest value for the slope therefore this would be the answer.

ANSWER: 12x - 6y = -24

Line ab is y = -7/5x + 56/5i don't understand  where point d comes into this.