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
Total number = 30
1/5 of 30 = 1/5 x 30 = 6
The attached figures show the total number of filled
circles in five lines. Each line have “6” filled circles.
So 5 lines having 6 filled circles = 5 x 6 = 30
<span>Every line represents “1/5” of total amount “30”. Which
proved that 1/5 of 30 is equal to 6. </span>
Try this solution, if it is possible check it in the other sources.
P.S. for the radius of convergence: it is clear that all the members of the series (except the 1st and the 2d ones) are '0'.