Engineers are designing a rollercoaster that at one point goes underground. The rollercoaster’s path underground is a large curve. The engineers use the function shown to model the elevation, ܧ ,in feet and ݐ , time, in seconds, of the rollercoaster’s path while it is underground.

One way to solve the quadratic equation x2  = 9 is to subtract 9 from both sides to get one side equal to 0: x2  – 9 = 0. The expression on the left can be factored:

(x + 3)(x – 3) = 0. Using the zero factor property, you know this means x + 3 = 0 or x – 3 = 0, so x = −3 or 3

Step-by-step explanation:

One way to solve the quadratic equation x2  = 9 is to subtract 9 from both sides to get one side equal to 0: x2  – 9 = 0. The expression on the left can be factored:

(x + 3)(x – 3) = 0. Using the zero factor property, you know this means x + 3 = 0 or x – 3 = 0, so x = −3 or 3

its a straight line parallel to the time axis