Answer:
d) 10°
Explanation:
The sum of supplementary angles always equal 180°.
Since two angles are supplementary, the two angles must add up to equal 180°. Angles A and B are known, so the equation is as follows.
![A + B = 180\\(6x + 4) + (10x + 16) = 180\\\\](https://img.qammunity.org/2022/formulas/mathematics/college/nkz9z0ad1intmdny2qyognz992itfpbc0o.png)
Rearrange and combine like terms:
![6x + 10x + 16 + 4 = 180\\16x + 20 = 180\\](https://img.qammunity.org/2022/formulas/mathematics/college/3gx6f5d5vzymlzy1wo83ktp61rxwoyhiv9.png)
Isolate x:
![16x = 180 - 20\\16x = 160\\x =10](https://img.qammunity.org/2022/formulas/mathematics/college/jeg3baj293jhx6631zs1701h4frgfv5rla.png)