What is the range of f(x)

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500

Ireally need subtract and simplify.(-y^2 – 4y - 8) – (-4y^2 – 6y + 3)show your work, ! i will mark you brainliest but you have to show your work.