Explain how you can use structure to find the last number in the bottom row

The depth of a lake at a certain point, wich is a function of the distance of that point from shore, is 30 feet.

Adozen bananas weigh 3 pounds how many ounces does 1 banana weigh

Adj has a total of 1075 dance and rock songs on her system. the dance selection is 4 times the size of the rock selection. write a system of equations to represent the situation.