What is the answer to x-5y

x-5y cannot be further simplified unless x and/or y is unknown.

In the case that you know what x is then you can isolate and solve for y, if you know what y is, then it is the other way around.

If you know both of the variables values, then you can simply just replace the variables and solve.

∠acb = 8°

step-by-step explanation:

∠xba lies on the circle and is half the measure of the intercepted arc ax

hence

measure of arc ax = 2 × 42° = 84°

∠acb is outside the circle and is

∠acb = (arcab - arcax ), hence

∠acb = 0.5 (100 - 84) = 0.5 × 16° = 8°