5n/4 = 1/5

i know the answer but don't know how it got there

What is the missing constant term in the perfect square that starts with x^2 -20x

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50. write an inequality to determine the number of chores, c, janie could do to have enough money to buy the cd.

Me find the value of x each figure.