*100 i really need . correct answer will get the brainliest answer. y = -­4x^2 ­- 2

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.

The distance between a football fsaid and a parking lot is 135 feet. what is that length in yards? 2 mickey needs to cut pieces of ribbon that are each 1 meter long to tie onto balloons. if he has 8 pieces of ribbon that are each 1 dekameter long, how many 1-meter pieces of ribbon can he cut? show work

The 7th grade has collected $200 for a field trip that would cost $600. the teachers decided to ask $50 from additional students to cover the cost. how mny students must pay to cover the cost ? a 16studentsb 80studentsc 160studentsd 8students show work