Evaliate each expression for the given value of x what is 2x+3 for x=3

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

Solve for x where 0 equation: cot^2x+2cotx+1=0

What is 10+10+20 about the origin the square root of a triangle.