So we have to find out what x is before we can solve for either angle
because vertical angles are always congruent we can set the two equations to equal each other and solve for x
so
-3x + 58 = x - 2
we need to get all the x terms on one side before we can solve for x so let's add 2 to both sides to get x alone on the right side
now we have
-3x + 60 = x
now we add 3x to both sides
60 = 4x
we isolated the terms and now we can solve for x by dividing both sides by 4
15 = x
so if x = 15 we need to plug that in to both equations to check our work
C = -3(15) + 58
C = 13
D = 15 - 2
D = 13
x does in fact equal 15 because both equations got the same answer and we found out that angle D = 13