Answer:
Ben is incorrect
The solutions are x>-3 and x < 3
Step-by-step explanation:
we have

Multiply by -1 both sides

Adds 9 both sides

The solutions are

and
-----> Multiply by -1 both sides ----> 
therefore
The solution is the interval (-3,3)
Ben is incorrect
Cos^4(x) =
(cos²x)² =
(1-sen²x)² =
1² - 2*1*sen²x + sen^4x =
1 - 2sen²x + sen^4x
Answer:
the last one i think
Step-by-step explanation:
Answer:
C
Step-by-step explanation:
We know every triangle equals 180 so were just going to take 180 - 42 = 138 then were going to do 138 - 67 = 71 we can check our work by doing
42 + 67+ 71 = 180. We also know 67 + 42 = 109.
Lets look at our answers;
A. 109 = 180 + x When solved it gave me; x = -71. We got a positive 71 so this is incorrect.
B. x + 42 = 67 When solved it gave me; x = 25, which is incorrect.
C. x = 180 - 109 When solved it gave me; x = 71
D. 42 + 67 - x = 180 When solved it gave me; x = - 71
Therefore the answer is C.