3) A linear equation to represent this would be 205 = 10x + b
x is days passed, which is 10, and b is the original amount.
10 times 10 is 100, so we now have 205 = 100 + b
Subtract 100 from both sides to get 105 = b, which is the starting amount.
The rate of change is 10, however many cans brought per day.
4) So it appears that for every 5 minutes she frosts 4 cupcakes, which means the rate of change is 4/5 using rise over run.
Subtract 4 from 28 to get the starting amount 5 minutes earlier.
The starting amount of frosted cupcakes is 24.
5) Every 3 months he gets 9 more CDS. So, every month he gets 3 new CDs.
That means the slope is 3.
Subtract 9 from 18 to get the starting amount.
The starting amount of CDs is 9.
Hope this helps!