Roxy used a calculator to evaluate (18+ 2) × (49 - 34) - 63 +9 by entering c 18+ 2 * 15 - 7 into a calculator. which
statement is true?
the calculator will show the correct value because 2 should be multiplied by 15 first.
the calculator will show the correct value because 7 should be subtracted from 18 first.
the calculator will show an incorrect value. she should have added 18 and 2 and then entered c 20 * 15 - 7 into the
calculator
the calculator will show an incorrect value. she should have subtracted 7 from 15 and then entered c 18 + 2 * 8 into
the calculator

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.