Simplify the expression: 9 x + 4 y minus 7 x + 2 y.
a. 2x2 + 6y2
b. 2x + 6y
c. 8xy
d. 8x2y2

If there is 20 dogs in the shelter and 5 dogs get homes, and then 43 more dogs come. how many dogs are there in the shelter?

Assume that there is a 11% rate of disk drive failure in a year. a. if all your computer data is stored on a hard disk drive with a copy stored on a second hard disk drive, what is the probability that during a year, you can avoid catastrophe with at least one working drive? b. if copies of all your computer data are stored on four independent hard disk drives, what is the probability that during a year, you can avoid catastrophe with at least one working drive?

Reading tests are compared for two students. sara got 98, 100, 65, 78, 98, 46, 100, 100, 45, and 50 on her reading test. lee got 97, 67, 89, 99, 100, 45, 79, 89, 58, and 67 on his reading test.