Jane needs $20 to buy her radio. she has saved $15. what percent of the cost of radio has she saved?

In simplified exponential notation, the expression a^2•a^-3•a 1/a 0

Given the points a(-2, 1) and b(8, 6), find the coordinates of the point c on directed line segment ab, that partitions ab in the ration 2: 3.

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.