Answer:
b-4/5b
Step-by-step explanation:
b is decreased by 80%
dat is 80/100×b
= b-80/100b
b-4/5b
Answer:
$5.00
Step-by-step explanation:
Since the eyeliner went up and doubled in price, you simply multiply 2.50 by 2, and you get $5.00
Answer:
6/5 or 1.2, they're the same value
Step-by-step explanation:
When it says "rate of change", it's really just asking for the slope. If you don't know what the slope is, essentially how much the y-value increases by whenever x increases by 1. This can be formally defined using the equation: 
which is essentially 
. The subtraction is finding the difference between the two numbers to see how much it's changed by. Btw the order doesn't matter, I could plug in (-3, -2) as (x2, y2) or I could plug it in as (x1, y1) as long as I make sure to input it in correctly. In this example I'll just say (-3, -2) = (x1, y1) and (2, 4) = (x2, y2). Plugging these values into the equation gives you: 
that's the rate of change
