Solve the system of equations by substituion,
-5x + y = 3
7.5x - 1.5y = 3

The volume of a sphere is increased by 6%. calculate the corresponding percentage increased in it area.

X+ y = 5 ; x - y =3 solve using linear combination

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.