If you triple four and subtract two every day how many days until you have zero

Which is the equation of an ellipse with directrices at x = ±4 and foci at (2, 0) and (−2, 0)?

How much dextrose 70% must be mixed with dextrose 5% to prepare 1,000 ml of dextrose 20%?

21 type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar. the solution set of n2 - 14n = -45 is { (separate the solutions with a comma)