sin(x) = 3/5, being a positive value, must be in the first or second quadrants, with cos(x) < 0 as well meaning that it is in the second quadrant. Draw a right angle triangle with opposite side 3 units and hypotenuse 5 units, use Pythagoras to find the adjacent side (if you can't already tell it's a 3,4,5 triangle), state what cos(x) is, and note that you need to negate this value because you're in the second quadrant.

Follow similar procedures for the rest.