For the first one, you do 153=x-4+2x+10 (due to the exterior angle theorem) and x will be equal to 49 or A. For the second one, you do 60 +7x+5=20x, which x is equal to 5 and the answer is C.
The exterior angle theorem is basically saying the two angles on the inside (interior angles) that are not touching or adjacent to the outside angle (exterior angle) form by the line is equal to exterior angle when they are added together.
