Answer:
Step-by-step explanation:
2b + 2c
Answer:
1080°
Step-by-step explanation:
formula to find the sum of interior angles of a polygon is (n-2)×180
octagon has 8 sides so n=8
(8-2)×180
6×180
=1080°
Answer:
1 + root 5, 1 - root 5
Step-by-step explanation:
I assume you mean 3x^2-6x-12=0.
First, note that you can divide both sides by 3. You get:
x^2-2x-4=0
Use the quadratic equation.

Therefore, x=1 + root 5, 1 - root 5