Suppose the number in this case to be n.
According to the statement given, six times of number would be 6n
and
the sum of 6 times the number (6n) and nine would be ---> 6n + 9
is equal to the difference of the number (6n) and eleven ---> n - 11.
So, the final equation becomes:
6n + 9 = n - 11
Solving this, place both the values of n on one side and the numbers on the other side but do not forget to change the sign of the value that you change the side of.
6n - n = -11 -9 (here we changed the signs of positive n to -n and positive 9 to -9 because we changed their sides)
5n = -20
n = -20/5
n = -4