Determine if the expression is a polynomial or not please help, ill mark brainlest if your right♡︎♡︎♡︎

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

Find an equation of the line perpendicular to the graph of 28x-7y=9 that passes through the point at (4,1)

Alicia puts $400 in a bank account. each year the account earns 5% simple interest. how much money will be in her bank account in six months?