X = 15°
Given that the angle with m < 165° and m< x° are supplementary angles whose sum add up to 180°,
We can add their sum by establishing the following formula:
m < 165° + x° = 180°
Subtract m< 165° from both sides
m < 165° — m < 165° + x° = 180° — m < 165°
x° = 180° — m < 165°
x° = 15°
Therefore, the value of x = 15 °