What is the rate of change on [-1,4]​

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?

Ten times the square of a non-zero number is eqaul to ninety times the number

The surface area of the triangular prism is .