= 3 - 3cos x - 2(1- cos^2 x)
= 2cos^2 x - 3cos x + 1
=(cos x -1)(cosx - 1/2)
now cos x = 1 or cos x= 1/2
draw a graph we get = + ve values
hence .. 0 ,180,360 and 60,240, degrees in range x<2pi
Answer C : 3x^2+7xy-2y^2
equivalent to the following expression


Combine like terms

2x^2 + x^2 is 3x^2
4xy+3xy is 7xy
-y^2-y^2 is -2y^2
So expression becomes

Answer C is correct
Answer:-infinity,infinity
Step-by-step explanation:
None
Answer:
x = 55° (nearest degree)
Step-by-step explanation:
Trig ratios:

where
is the angle, O is the side opposite the angle, A is the side adjacent to the angle, and H is the hypotenuse of a right triangle
Given:

- A = 3.3
- H = 5.7


⇒ x = 55° (nearest degree)