Answer: see proof below
<u>Step-by-step explanation:</u>
Given: cos 330 = 
Use the Double-Angle Identity: cos 2A = 2 cos² A - 1

Proof LHS → RHS:
LHS cos 165
Double-Angle: cos (2 · 165) = 2 cos² 165 - 1
⇒ cos 330 = 2 cos² 165 - 1
⇒ 2 cos² 165 = cos 330 + 1
Given: 

Divide by 2: 

Square root: 
Scratchwork: 

Since cos 165 is in the 2nd Quadrant, the sign is NEGATIVE

LHS = RHS 
Answer:
positive 3
Step-by-step explanation:
-8 + 11 is 3. the other way you can think of it is by subtracting 8 from 11.
Answer:
-4 a^2 - 3 b
Step-by-step explanation:
Answer:
1 and 2) After multiplying (x+y+3)(y+1) we have
Which is an equivalent expression after applying the distributive property.
As we can see we have an one of the variables squared, so we obtain an Parabolic Cillinder