An observation deck extends 118 feet out above a valley. The deck sits 68 feet above the valley floor. If an object is dropped from the observation deck, its height in feet, after t seconds, is given by h= -16t^2+ 68. How long will it take for the object to be 4 feet above the valley floor?

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

Solve the system of equations y= 3/2 - 1, -x+ y =-3

Ellen makes and sells bookmarks. she graphs the number of bookmarks sold compared to the total money earned. why is the rate of change for the function graphed to the left?