Rewrite the function by completing the square f(x)=x^2+4x+41

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

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?

What are the intercepts of x^2+y-9=0