Let r1, ..., rp be vectors in set of real numbers R Superscript n, and let Q be an m n matrix. Write the matrix [Upper Q Bold r 1 ...Q Bold r Subscript p ]as a product of two matrices (neither of which is an identity matrix).

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.