His mistake was in multiplying the 3 with the 12. He should have divided it from the 12 because that would have gotten rid of the 3 with the variable. It would also lead to the correct answer, which is b=4
100 miles ............... 2 hours
x miles ................1 hour
x = 100 m / 2 h = 50 m / h
Step 1: Find the slope:
Step 2: Set up your equation 
using one of the points.
Using (5,6) we have 
.
Using (6,10) we have 
Both of those equations would be correct.
Answer:
<h2>f(x) = 3x + 4</h2>
Step-by-step explanation:
f(x + 1) = 3x - 7
f(x) = f(x + 1 - 1) = 3(x - 1) + 7 = 3x - 3 + 7 = 3x + 4
Check
f(x) = 3x + 4
f(x + 1) = 3(x + 1) + 4 = 3x + 3 + 4 = 3x + 7 CORRECT
-1 or option c is correct. Use the given functions to set up and simplify f(−2).
