How many different arrangements of 5 letters can be formed if the first letter must be W or K​ (repeats of letters are​ allowed)? There are ___ different ​5-letter combinations that can be formed.
​(Simplify your​ answer.)

Bismuth-210 is an isotope that radioactively decays by about 13% each day, meaning 13% of the remaining bismuth-210 transforms into another atom (polonium-210 in this case) each day. if you begin with 233 mg of bismuth-210, how much remains after 8 days?

[15 points]find the quotient with the restrictions. (x^2 - 2x - 3) (x^2 + 4x + 3) ÷ (x^2 + 2x - 8) (x^2 + 6x + 8)

What adds to be the bottom number but also multiplies to be the top number with 8 on the bottom and 15 on top