The half-life of a substance is how long it takes for half of the substance to decay or become harmless (for certain radioactive materials). the half-life of a substance is 123 days and there is an amount equal to 150 grams now. what is the expression for the amount a(t) that remains after t days, and what is the amount of the substance remaining (rounded to the nearest tenth) after 365 days? hint: the exponential equation for half-life is a(t) = a0(0.5)t/h, where a(t) is the final amount remaining, a0 is the initial amount, t is time, and h is the half-life.

Jeffery conducted a survey in his school and found that 30 of the 50 eighth grade students' favorite subject is mathematics. based on the results, jeffery concluded that out of the 200 students in his school, 120 students' favorite subject is mathematics. select the statement that is true about jeffery's conclusion. a. jeffery's conclusion is not valid because the sample was biased since only 200 students were surveyed. b. jeffery's conclusion is valid because the sample was random since all of the students were eighth grade students. c. jeffery's conclusion is valid because the sample was random. d. jeffery's conclusion is not valid because the sample was biased since all of the students were eighth grade students.

Will possibly give brainliest and a high rating. choose the linear inequality that describes the graph. the gray area represents the shaded region. 4x + y > 4 4x – y ≥ 4 4x + y < 4 4x + y ≥ 4

If the perimeter of the square equals the perimeter of the regular pentagon. each side of a pentagon is 16cm long. how long is each side of the square?