Answer: 
<u>Step-by-step explanation:</u>
Note the following identities: tan² x = sec²x - 1

tan² x + sec x = 1
(sec² x -1) + sec x = 1
sec² x + sec x - 2 = 0
(sec x + 2)(sec x - 1) = 0
sec x + 2 = 0 sec x - 1 = 0
sec x = -2 sec x = 1

Answer:
okay
Step-by-step explanation:
complementary angles are angles that add up to 90 degrees
so what you would do is take each number that you have and subtract it from 90
In the first one you would
1. take 90-80
2. you get your answer of 10!
i hope this helps :)
Answer:
A. 2 in.
Step-by-step explanation:
This looks like scalar matrix multiplication. The idea here is to multiply the scalar 3 by each item inside the matrix.
Doing so leads to the answer [3 -12 15 -21]
Side note: I'm assuming the matrix given to you has 1 row and 4 columns.