What is k?

2k + 7k − 11 = 58

a: k= 6, 4/9
b: k= 5, 2/9
c: k= -13 4/5
d: k= 7, 2/3

these are fractions, the first number is the whole number.

Evaluate the integral. (sec2(t) i t(t2 1)8 j t7 ln(t) k) dt

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?

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?