Solve the system of equations -4x+5y=64−4x+5y=64 and -x+y=12−x+y=12 by combining the equations.

1. what is the measure of ∠abc? what is the measure of ∠abd?

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.

Milk and ice cream are mixed together for a recipe. the total volume of the mixture is 1 cup. if the milk contains 2% fat, the cream contains 18% fat ,and the mixture contains 6% fat ,how much cream is in the mixture