What is the x-value of the vertex of f(x) = -x2 + 9x - 11 ?

David bought a poster for an art project. the poster is 2.7 feet wide and 3.9 feet tall. what is the area of the poster?

The holiday party will cost $160 if 8 people attend. if there are 40 people who attend the party, how much will the holiday party cost

Amir wants to proportionally increase the size of a photo to create a poster for his room. the size of the original photo is shown. complete the statement and then answer the question to represent ways that amir can increase the size of his photo.