These periods mark blank and blank

Which of the following expressions is equivalent to -1/4y - 2 1/4 + 1/2 (4-2y)? a. -3y + 2b. -3 1/2+4c. -4 1/2y+2d. -4 1/2y+2show ur work

The first atomic explosion was detonated in the desert north of alamogordo, new mexico, on july 16, 1945. what percentage of the strontium-90 ( yr) originally produced by that explosion still remains as of july 16, 2016?

What is the process that powers plate tectonics