The measure of an angle a is (2x°)and the mesure of its supplement ,angle b is(x-6)°.what is the measure of each angle.

Remark
The measure of the two angles add to 180. That permits you to solve for x.

Givens
1. Supllementary angles add to 180o
2. A = 2x
3. B = x -6

Equation
A + B = 180
2x + x - 6 = 180

Solution
2x + x - 6 = 180     Combine like terms
3x - 6 = 180           Add 6 to both sides
3x = 180 + 6
3x = 186                Divide by 3
x = 186/3
x = 62
Answer
A = 2x
A = 124

B = x - 6
B = 62 - 6
B = 56

I'm sorry to say that I'm not getting any of them. The intended answer is likely B which I would try first. A and D do not add to 180. C does add to 180 but it looks like the answer was derived by taking x to be one of the angles and then the supplement would be 180 - 62 = 118.

A D and C are all incorrect. B is not either, but it is the closest.