Please answer me anybody???i'm in a great trouble...please
If a^4-1/a^4=m^4+4m^2+2 then prove that a^2-1=ma

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?

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Ineed in figuring out this problem.