### Home > CCA2 > Chapter 8 > Lesson 8.1.3 > Problem 8-54

8-54.

What is the stretch factor for the equation of the graph in part (c) of problem 8-45? Write the exact equation of the function. Homework Help ✎

Using the factors, you can work backwards to find the beginning of the equation. The double root at *x* = −2 gives you (*x* + 2)^{2}, the root at *x* = 1 gives you (*x* − 1). Substitute the point (0, 8) into the equation *y* = *a*(*x* + 2)^{2}(*x* − 1) and solve for *a*.

The stretch factor is −2. The equation is *f*(*x*) = −2(*x* + 2)^{2}(*x* − 1).