Chapter 1.7, Problem 49E

M = log The formula determines the magnitude of an earthquake, where / is the intensity of the earthquake and S is the intensity of a "standard earthquake." How many times stronger is an earthquake with a magnitude of 8 than an earthquake with a magnitude of 6? Show your work.

Now consider equations of the form ×-a=v = √bx + c, where a, b, and c are all positive integers and b>1. (f) Create an equation of this form that has 7 as a solution and an extraneous solution. Give the extraneous solution. (g) What must be true about the value of bx + c to ensure that there is a real number solution to the equation? Explain.

The equation ×+ 2 = √3x+10 is of the form ×+ a = √bx + c, where a, b, and c are all positive integers and b > 1. Using this equation as a model, create your own equation that has extraneous solutions. (d) Using trial and error with numbers for a, b, and c, create an equation of the form x + a = √bx + c, where a, b, and c are all positive integers and b>1 such that 7 is a solution and there is an extraneous solution. (Hint: Substitute 7 for x, and choose a value for a. Then square both sides so you can choose a, b, and c that will make the equation true.) (e) Solve the equation you created in Part 2a.