In exercises 11-13 use euler's formula f + v = e + 2 to find the number of faces, edges or vertices.
11. a prism has 6 faces and 8 vertices. how many edges does it have?
12. a pyramid has 4 faces and 4 vertices. how many edges does it have?
13. a pyramid has 8 edges and 5 vertices. how many edges does it have?

Nine more than four times a number is the same as one less than twice the number. find the number?

Atype of plant is introduced into an ecosystem and quickly begins to take over. a scientist counts the number of plants after mmonths and develops the equation p(m)= 19.3(1.089)^m to model the situation. most recently, the scientist counted 138 plants. assuming there are no limiting factors to the growth of the plants, about how many months have passed since the plants werefirst introduced? a)o 6.1b)0.6.6c)10 72d)o 23.1

Tommy buys a sweater that is on sale for 40% off the original price. the expression p -0.4p can be used to find the sale price of the sweater, where p is the original price of the sweater. if the original price of the sweater is 50, what is the sale price?