Answer: Let's say,
y = the amount of money Perry will owe his brother after n months.
x = the principal (the initial amount borrowed) = 150
r = the interest rate per month = 7/100 = 0.07
n = number of months.
We know that Interest on a loan is calculated by multiplying the principal by the interest rate.
Therefore, the interest for n months is (0.07*x)*n
So to find the total amount Perry will owe his brother after n months, we need to add the interest to the principal amount.
y = x + interest
y = x + (r*x)n
y = x(1 + rn)
Therefore, the rule in the "y =..." form that will give the amount of money, y, Perry will owe his brother after n months, assuming that he doesn't make any payments is:
y = 150(1 + 0.07*n)
It's worth noting that this formula can be used to calculate the amount he will owe after any number of months by changing the value of n, and It's assuming he doesn't make any payments, meaning if he makes any payments, the total amount he will owe will change.
Explanation: