y = mx + b
To find the slope(m), you use the slope formula:

You plug in the points into the equation.


The slope is 0
y = 0x + b
Any number multiplied by 0 is 0. So:
y = b
To find b, you plug in the y value of either of the points.
-4 = b
Your equation is:
y = -4 (This is a horizontal line)
To solve this answer, you are trying to find 55% of 600, because that is the number of people who chose plastic bag.
55% can be re-written as 55/100 OR 0.55 since percentages are always out of 100.
So, we do 0.55*600, which gives us 330. 330 people carry plastic bags.
So basically you counting by 3