We are given that our fingernails grow at a rate of 0.7 millimeters each week. We can write this rate of change as an expression.
0.7 ml/1 week ⇒ m=7/10To graph the function we also need the y-intercept. We are given that r( 0)= 12, so we can identify the y-intercept as ( 0, 12). Now we have enough information to graph the function.
Notice that our domain is being restricted to the first quadrant because we cannot go back in time or have a negative growth of fingernails.
Interpretation of the y-intercept
As we previously found, the y-intercept is (0,12). Since the y- indicates the right index fingernail's length, we can say that fingernail is initially 12 millimeters long.
