Seventeen divided by four less than a number in numeric form

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?

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

Add the fractions and simplify 1/2+ 1/3