Simplify 4.2^-3 x 5.1^2 x 4.2^4 x 5.1^3

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

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?

Anormally distributed data set has a mean of 176.3 and a standard deviation of 4.2. what is the approximate z-score for the data value of 167.9? 2.00 −2.00 8.4 −8.4