What can be said about 10 and -10?

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.

Given the equation    = 5, solve for x and identify if it is an extraneous solution

Angle 1 and 2 are a linear pair. angle 1 equals x-39 and angle 2 equals x+61 . find the measure of each angle