The final step of completing a "solve by substitution" problem is to A. solve for the remaining variable
B. write your solution as an ordered pair
C. substitute your solution into one of the equations in the system to check your solution
D. substitute your solution into both of the equations in the system to check your solution
Please select the best answer from the choices provided
ОА
X B

Given the following statements, which is the best

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 the number of real number solutions for the equation. x2 + 5x + 7 = 0 0 cannot be determined 1 2