The width of a rectangle is 8n -3.5 feet and the length is 3.5n+6 feet. Find the perimeter of the rectangle.
The perimeter of the rectangle is feet. .
(Simplify your answer. Use integers or decimals for any numbers in the expression.)

need help please

Which expression is equivalent to −16y+13 ? −16(−y+13) 16(−y+2) −16(y+2) 16(−y+13)

Anyone know? will mark brainliest if correct!

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