Question

How do I get the equation for the first part in algebraic terms?

Answer 1

If he starts out with 40 dollars and has 50 by week one, he's added 10 dollars. So you see the trend that each consecutive week he adds 10 more dollars throughout the chart. If we say the variable 'A' represents the amount of money he'll have and 'n' is the amount of weeks, then A = 10n + 40. This is because he starts out with 40 dollars (the +40) and what is added to that original amount is 10 dollars multiplied by however many weeks have passed (10n). Then that leaves you with the amount.

Answer 2

First you find the rate of change, which is how much she is making per week. If she starts with $50 then has $60 she gained $10, then the following week she has $70 gaining a consistent $10 a week. So now you add $10 a week to what you started with. Ending with 50+10x and for the 8th week you would substitute 8 for x getting $130