Simplify (x^-1-(x+1)^-1)^-2

Vip at (-2,7) dropped her pass and moved to the right on a slope of -9 where can you catch up to her to return her vip pass

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?

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?