How would you rewrite 5 to the -15 power as a positive exponent

Hello everybody. can anybody me come up with detailed study plan on what topics to study from algebra 1 & 2, trig, and any other topic nesscery for success as a new beginner in pre-calculus. i dont have much math history but the basics. this will greatly me.

Allie answered 72% of the questions on her math test correctly. if she answered 18 questions correctly, how many questions were on the test?

Iq scores for adults age 20 to 34 years are normally distributed according to n(120, 20). in what range does the middle 68% of people in this group score on the test?