Which expression is equivalent to the expression shown 5^3^9 / 5^12

The table represents a linear function. what is the slope of the function? –6 –4 4 6

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.

Arectangular courtyard is 12 feet long and 8 feet wide. a tile is 2 feet long and 2 feet wide. how many tiles are needed to cover the courtyard?