Im new at this so im chilling right now

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?

26) -2(7x) = (-2 • 7) x a. associative property of addition b. associative property of multiplication c. commutative property of multiplication d. commutative property of addition

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2