The half-life of radium-226 is 1590 years. (a) a sample of radium-226 has a mass of 200 mg. find a formula for the mass of the sample that remains after t years. (b) find the mass after 1000 years correct to the nearest milligram. (c) when will the mass be reduced to 30 mg?

Use the normal approximation to the binomial distribution to answer this question. fifteen percent of all students at a large university are absent on mondays. if a random sample of 12 names is called on a monday, what is the probability that four students are absent?

Find the equation of the line that goes through the points (4, –1) and (2, –5). use slope formula,equation,to find the slope of a line that passes through the points. m = use slope-intercept form, y = mx + b, to find the y-intercept (b) of the line. b = write the equation in slope-intercept form, y = mx + b.

Square a has a side length of (2x-7) and square b has a side length of (-4x+18). how much bigger is the perimeter of square b than square a?and show all work! you so