Quick CAST question

Okay, am I right in saying; if I have the question, solve sin/cos/tan 2x = random number, I would multiply the range by 2 to get the new range, solve to get all the values of 2x, then divide the values by 2 to get my x values.

If the question is sin/cos/tan (x-50) = -sqrt(3)/2, would I subtract 50 from the range and then add 50 onto my final answers to get x? Abit confused atm.