Students in grades 7 and 8 were asked which food they liked best. The results are shown in the table. Favorite Food
Pizza Hot Dog Hamburger Total
40 25 35 100
Grade 7
Grade 8
35
30
35
100
Total
75
55
70
200

At which value in the domain does f(x) =0?

The rate of decay of a radioactive substance depends upon the amount present initially. the mass y (mg) of the radioactive substance cobalt-60 present in a sample at time t (years) is represented by the exponential equation y=50e −0.1315 t . answer the following questions in complete sentences. 1. how does the exponential equation above compare to the equation for simple interest that is compounded continuously? explain the similarities. 2. what is the initial amount of cobalt-60 in the sample? 2. how much cobalt-60 is left after 8.4 years? show your work. 3. what would be the y-intercept of the graph? what does it represent? 4. after how many years will the amount of cobalt-60 left be 6.25 mg? explain what happens to the cobalt-60 after 50 years? 5. discuss some “real-world” examples and uses of cobalt-60

If you answer 2+2 you will get over 80 points