What is the square root of 125

Consider the function f(x)=-5x+3 what is f(-2)

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.

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