How many permutations are possible in the word numbers?

Find the slope of a line given the following two points

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9

Find the equation of the ellipse with the following properties. the ellipse with foci at (0, 6) and (0, -6); y-intercepts (0, 8) and (0, -8).edit: the answer is x^2 over 28 + y^2 over 64 = 1