Answer:

Step-by-step explanation:
A quadratic expresion is of the form

where

The give options are:




From the given options, the only expression which is quadratic is

where a =5, b=9 and c=-1
Therefore the correct choice is the second option.

<u>Step-by-step explanation:</u>
Here we have , cos x = -4/5 ( corrected as given -45 which is not possible ) ,
180° < x < 270° i.e. in third quadrant . We need to find tan(2x) . Let's find out:
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
⇒
, since in third quadrant .
remains same .
Now , 
⇒ 
⇒ 
⇒ 
⇒ 
Therefore,
.
A.0 represents an acute angle because acute angles have to be less than 90
Answer:
your mom
Step-by-step explanation: