a + b + c = 30 ;
a = 6c ;
a = 2b ;
Then, c = a / 6 and b = a / 2 ;
a / 6 + a / 2 + a = 30 ;
a / 6 + 3a / 6 + 6a / 6 = 180 / 6 ;
10a = 180 ;
a = 18 ;
b = 9 ;
c = 3.
Good luck !
Given:

To find:
The exact value of cos 15°.
Solution:

Using half-angle identity:


Using the trigonometric identity: 

Let us first solve the fraction in the numerator.

Using fraction rule: 

Apply radical rule: ![\sqrt[n]{\frac{a}{b}}=\frac{\sqrt[n]{a}}{\sqrt[n]{b}}](https://tex.z-dn.net/?f=%5Csqrt%5Bn%5D%7B%5Cfrac%7Ba%7D%7Bb%7D%7D%3D%5Cfrac%7B%5Csqrt%5Bn%5D%7Ba%7D%7D%7B%5Csqrt%5Bn%5D%7Bb%7D%7D)

Using
:


Answer:
A b and c
Step-by-step explanation:
D might be true but i am not sure
1. -3x + -6
2. -3x + 9
3. 2x - 6
4. -2x + 6
here u go