Hey there!
"What ratio forms a proportion with
?"
-
(for the decimal)
But in order for you to solve this particular equation you'd have to go in with two (like multiplying by two)
Your result: 
Good luck on your assignment and enjoy your day!
~
On Monday she sold 5 books
monday=5 books
tuesday=5 times 2 = 10
wednesday= 10-6=4
5+4+10=19
m=19+6 divided by 5
Expand the following:
(s^2 - t^(-2))/(s - 1/t)
(s^2 - t^(-2))/(s - 1/t) = s^2/(s - 1/t) - (1)/((s - 1/t) t^2):
Answer: s^2/(s - 1/t) - 1/(t^2 (s - 1/t))