Will mark brainliest to anyone who gets the right answer.

suppose a laboratory has a 31 g sample of polonium-210. the half-life of polonium-210 is about 138 days. a. how many half-lives of polonium-210 occur in 966 days? b. how much polonium is in the sample 966 days later?

7; 2,139 g

8; 0.12 g

7; 0.24 g

7; 4.43 g

Look at this system of equations. -3x + 3y = 12 y = x + 4 the solution set of this system is best explained by which of these statements? a) the graphs of the equations are the same line because the equations have the same slope and the same y-intercept. the system has infinitely many solutions. b) the graphs of the equations are parallel lines because they have the same slope but different y-intercepts. the system has no solution. c) the graphs of the equations are lines that intersect at one point because the equations have the same slope but different y-intercepts. the system has exactly one solution. d) the graphs of the equations are lines that intersect at one point because the equations have the same slope and the same y-intercept. the system has exactly one solution.