O think it is c subtracting 6 because adding and subtracting is the same so it’s either c or d
Answer:
The mean of the numbers are 1
QUESTION 1
The given function is

We simplify to get;

This function is equal to zero when 

QUESTION 2
The given function is
We factor to get;
This function equals zero when


QUESTION 3
The given function is

We factor to get,


The function equals zero when 



Hence the equation has no real roots.
The complex roots are
or 
I hope my answer is correct
Ok so, 15 of them know how to play whist (I have no idea what that is) and 20 of them know how to play dominoes, 5 of them do not. So, if you add up 20+15=35, take off 10 35-10=25 so it must mean that 10 is the answer. (Also if you add 5 to that 25+5=30)
The Answer is 10