We can use a rule of three simple, direct proportion to solve this problem.
15 pounds correspond to $1.80, then the question is to find the price of one pound, the called unit rate. We state the rule of three:
15 pound ----> $1.80
1 pound -----> x
x = (1)(1.80)/15
x = 0.12
Therefore, each pound costs $0.12 that is the unit rate in pounds
X decreased by the square of nine
x - 9^2 = x - 81
Answer:
2,3,4,5,6,7,8,9,10, that's it easy
