Can someone simplify the definition underneath please

Xto the second power plus 14x plus 48. what are the factors? we are doing factoring trinomials with a=1

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?

Type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar.