At the store, you buy some pencils for $0.50 each and some pens for $1.50 each. you spend a total of $12 and purchase 16 items (pencils and pens only). (a) write and solve a system of equations that model the problem. show all your work. (b) how many of each type of writing utensil did you purchase? (write your answer in a complete sentence)

The decibel level of sound is 50 db greater on a busy street than in a quiet room where the intensity of sound is watt/m2. the level of sound in the quiet room is db, and the intensity of sound in the busy street is watt/m2. use the formula , where is the sound level in decibels, i is the intensity of sound, and is the smallest sound intensity that can be heard by the human ear (roughly equal to watts/m2).

The pyramid shown has a square base that is 24 centimeters on each side. the slant height is 16 centimeters. what is the lateral surface area?

Ntriangle abc, m∠a = 35° and m∠b = 40°, and a=9. which equation should you solve to find b?