### Home > PC > Chapter 9 > Lesson 9.3.5 > Problem 9-156

9-156.

Show that the equation of the tangent line to the curve *y* = 12*y* = 3*x* + 12. Homework Help ✎

Use the point - slope form for a linear function.

You are given a point. So now you need the slope of the tangent line.

1. Find the slope function at *x* = 4.

2. Graph the slope function.

3. As *h*→0, what does the slope approach?

Use the slider in the eTool below to see that the slope at *x* = 4 is 3. Then find the equation of the tangent line with the given point and slope.

Click the link at right for the full version of the eTool: PCT 9-156 HW eTool