Christopher's backyard is in the shape of a trapozoid. the bases of his backyard are 30 and 40 feet long. the area of his back yard is 525 square feet. write and solve an equation to find the height of christopher's back yard.

Does the problem involve permutations or? combinations? do not solve. the matching section of an exam has 4 questions and 7 possible answers. in how many different ways can a student answer the 4 ? questions, if none of the answer choices can be? repeated?

2y= 3 2 x−2 y = − 1 3 x + 1 y=− 3 1 x+1

Aculture started with 3000 bacteria. after 5 hours it grew to 3900 bacteria. predict how many bacteria will be present after 9 hours