cell phone plan costs $23.90 per month for 700 minutes of talk time. It costs an additional $0.08 per minute for each minute over700 minutes. To get email access, it costs 20% of the price for 700 minutes of talk time. Your bill, which includes e-mail, is the same each month for 5 months. The total cost for all 5 months is $169.00. Write and solve an equation to find the number of minutes of talk time you use each month.

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.