If 18 g of a radioactive substance are present initially and 9 yr later only 9 g remain, how much of the substance will be present after 12 yr? After 12 yr there will be g of a radioactive substance.
(Round the final answer to three decimal places as needed. Round all intermediate values to seven decimal places as needed.)

An arithmetic series a consists of consecutive integers that are multiples of 4 what is the sum of the first 9 terms of this sequence if the first term is 0

The frequency table shows the results of a survey asking people how many hours they spend online per week. on a piece of paper, draw a histogram to represent the data. then determine which answer choice matches the histogram you drew. in order here is the.. hours online: 0-3, 4-7, 8-11, 12-15, and 16-19. frequency: 5, 8, 10, 8, 7 answer for the question is in the picture! : )

Multiply and simplify. 2x^2 y^3 z^2 · 4xy^4 x^2 i will mark you brainliest if right. show how you got the answer, !