I need help with this slope problem

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

The height of a flare fired from the deck of a ship in distress can be modeled by h(t)= -2(8t^2-52t-28), where h is the height of the flare above water and t is the time in seconds. a. find the time it takes the flare to hit the water.

Write the equation in logarithmic form e^x=403.429