Im an idiot can someone please help?

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a

Atreasure chest sinks at a rate no less than 20 feet er second. the floor of the icean is at most at -4,200 feet. will the tresure chest reach the ocean floor in less than 3 minutes? explain.

Round the number to the hundredths place. 26,379.87492 a. 26,379.87 b. 26,379.88 c. 26,380 d. 26,400