Which description is paired with its correct expression? O seven less than the quotient of two and a number squared, increased by six;
7-
- 16
O nine times the difference of a number cubed and three; 9(nº-3)
O eight more than the quotient of a number squared and four, decreased by seven;
8+
O twice the difference of a number cubed and eight; 2n - 8

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.