From A Graph
Example 1 Continued

Step 3. Determine the factored form of the polynomial by using another point from the graph. Substitute the point in for (x, y) and solve for the value of a.

y = a (x + 1)(x)(x - 5); point (4, -40)

-40 = a (4 + 1)(4)(4 - 5)

-40 = a (5)(4)(-1)

-40 = a (-20)

2 = a

y = 2 ( x + 1)( x )( x - 5)