What is 4c?

c= [12 0 3/2]
[1 -6 7]

a. [48 0 12]
[4 -24 28]

b. [24 0 6]
[2 24 28]

c. [48 0 3]
[4 -24 28]

d. [48 0 6]
[4 -24 28]

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

This is my question~~ ( r ^ 4 - 2r ^ 3 - 23 r ^ 2 - 4r - 32)÷(r+4) ~~ i must use long division to solve it : / i was wondering if anyone world like to solve it. and if so, share step-by-step explanations! you! ❤

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.