Fraction with variable x in numerator and 6 in the denominator can written in the algebraic expression as

Let's assume some number is n.
So, the sum of six and some number can be written as 6+n.
The product of six and some number can be written as 6*n.
The quotient of some number and six will be n/6.
The difference of six and some number will be 6-n.