If m∠ABC = 80°, what is m∠DBC? Justify your reasoning. a- Using the Angle Addition Postulate, 20 + m∠DBC = 80. So, m∠DBC = 60° using the
subtraction property of equality.
b- Using the Angle Addition Postulate, 20 + 80 = m∠DBC. So, m∠DBC = 100° using the
addition property of equality.
c- Using the addition property of equality, 20 + 80 = 100, so m∠DBC = 100°.
d- Using the subtraction property of equality, 80 − 20 = 60, so m∠DBC = 60°.

a- Using the Angle Addition Postulate, 20 + m∠DBC = 80. So, m∠DBC = 60° using the

subtraction property of equality.

Step-by-step explanation:

ABD+ DBC = ABC  by the angle addition postulate

20 + DBC =  80

Subtract 20 from each side, using the subtraction property of equality

20+DBC-20 = 80-20

DBC = 60

55? i think maybe

step-by-step explanation:

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.