Example:

This suggests two solutions,

and

.
However, upon plugging these solutions back into the equation, you get

which checks out, but

does not because

is defined only for

(assuming you're looking for real solutions only). So, we call

an extraneous solution, and the complete solution set (over the real numbers) is

.
Using law of cosines:
Cos(angle) = adjacent/ hypotenuse
Cos(22) = 12/x
Rewrite to get:
X = 12/cos(22)
Simplify:
X = 12.9424
Round the answer as needed.
Answer:
0 and yes
Step-by-step explanation:
Let a=6m where m is any integer since a is divisible by 6. (a+12)/3=(6m+12)/3=2m+4 which is also an integer. The remainder is 0.
Since n is divisible by 3, n can be written as 3a, where a is any integer and m can be written as 2b, where b is any integer. n*m+12=6ab+12 which is divisible by 2.