Write an explicit formula for a_na n
​
, the n^{\text{th}}n
th
term of the sequence 45, 15, 5, ...45,15,5,

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.

What three-dimensional solid have 6 rectangular faces, 2 equal bases that are not rectangles and 18 edges

In a right triangle δabc, the length of leg ac = 5 ft and the hypotenuse ab = 13 ft. find: b the length of the angle bisector of angle ∠a.