Leticia simplified an expression. Her work is shown below. 4.5 divided by 0.25 + 2.5 minus 0.75 times 8 Step 1 18 + 2.5 minus 0.75 times 8 Step 2 18 + 1.75 times 8 Step 3 18 + 14 Step 4 32 In which step did Leticia make her first mistake? step 1 step 2 step 3 step 4

Agreeting card company can produce a box of cards for $7.50. if the initial investment by the company was $50,000, how many boxes of cards must be produced before the average cost per box falls to $10.50?

Choose the point slope form of the equation below that represents the like that passes through the points (-6,4) and (2, 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