The answer for this question is 36
1 cubic meter = 100 cm * 100 cm * 100 cm = 1 x 10^6 cc
1 kilogram = 1,000 grams
13.6 g / cc
If we had a cubic meter of mercury, its mass would be (or it would "weigh") 13.6 * 1,000,000 = 13,600,000 grams or 13,600 kilograms.
And so its density would be 13,600 kg / cubic meter.
Do you mean an extraneous solution? I will tell you what I think. To tell if a solution is extraneous you need to go back to the original problem and check if there actually is a solution or if the solution is actually right. If not then it is extraneous.
Answer:
and
.
Step-by-step explanation:
The equation can be simplified with the help of trigonometric identities:

Which means that equation is equal to zero if any component of the product is zero. The solutions of the expression are:
a) 

b) 



Any value different of both subsets do not satisfy the equation described above.