Answer:
answers are: (-1,-2), (1,2), (-1,5), (1,-5). in other words, option 2, 6, 7, and 8.
Step-by-step explanation:
hope it helps
Answer:
The correct option is C ) 109.5°
Therefore,

Step-by-step explanation:
Given:
In Triangle DEF
d = 10
e = 18
f = 12
To Find
angle E = ?
Solution:
In Triangle DEF , Cosine Rule says

Substituting the values we get


Therefore,

............As it is in Second Quadrant
Therefore,

The answer to this question is 2/3.
I believe you combine the first and last terms first because they have the same denominator
c or d for sure hope this helps