Ciara solved the exponential equation 3x+1 = 15 and her work is shown below. What is the first step she did incorrectly?

Step 1: log 3x+1 = log15

Step 2: (x + 1) log 3 = log15

Step 3: log3 = log 15 over x plus 1

Step 4: 0.477121 = 1.176091 over x plus 1

Step 5: 0.477121 (x + 1) = 1.176091

Step 6: x + 1 = 1.176091 over 0.477121

Step 7: x + 1 = 2.464975

Step 8: x = 1.464975

Question

Mathematics

Larry Medina

7 June, 20:42

Ciara solved the exponential equation 3x+1 = 15 and her work is shown below. What is the first step she did incorrectly?

Step 1: log 3x+1 = log15

Step 2: (x + 1) log 3 = log15

Step 3: log3 = log 15 over x plus 1

Step 4: 0.477121 = 1.176091 over x plus 1

Step 5: 0.477121 (x + 1) = 1.176091

Step 6: x + 1 = 1.176091 over 0.477121

Step 7: x + 1 = 2.464975

Step 8: x = 1.464975

+2

Answers (1)

Know the Answer?

Alison · Answer 1

The step that she did incorrectly would be step 3. For this we need to isolate the variable x. So, dividing x+1 should not be done because you are limiting the domain which is not main goal here. I hope this answers the question. Have a nice day.