Answer:
A, C
Step-by-step explanation:
Actually, those questions require us to develop those equations to derive into trigonometrical equations so that we can unveil them or not. Doing it only two alternatives, the other ones will not result in Trigonometrical Identities.
Examining
A) True

Double angle 
B) False,
No further development towards a Trig Identity
C) True
Double Angle Sine Formula 

D) False No further development towards a Trig Identity
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Use substitution
Given both y values, you know that they have to be equal
3x + 3 = x - 1
2x + 3 = -1
2x = -4, divide by 2
x = -2
Now plug x value into any of the equation to find y value
y = 3(-2) + 3
y = -6 + 3, y = -3
Solution: x = -2, y = -3
To solve this problem you need to figure out the volume of the sipping container, and the volume of the tissue box.
39*19.5*19.5=14,829.75
6.5*6.5*6.5=274.63
In order to figure out how many fits you need to divide
14,829.75/274.63=53.99
The maximum number that you can fit is the box is 53.
Hope this helps
Answer: 42 cm to the power of 3
Step-by-step explanation: L x w x h
3 x 7 x 2
21 x 2
42