How do you tell if a number is irrational or rational?

You're locked out of your house. the only open window is on the second floor, 25 feet above the ground. there are bushes along the edge of the house, so you will need to place the ladder 10 feet from the house. what length ladder do you need to reach the window?

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me

What is the effect on the graph of the function f(x) = x2 when f(x) is changed to f(x) − 4?