the quotient means divide.....the difference means subtract
the quotient of 5 and the difference of a number and 3..
5 / (x - 3) <== ur expression
the product means multiply....decreased means subtract
the product of a number and 20 decreased by 11..
20x - 11 <== ur expression
the difference means subtract
the difference of 30 and a number, multiplied by 2
2(30 - x) <== ur expression