What do you do to get this answer and what is the answer

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.

Binh says the point of intersections is (0,-3) which statements identify the errors binh made , check all that apply

What is the slope of the line that passes through the points (–9, 2) and (0, 4)? the slope of the line is