Solve the following system of equations by linear combination: 3d – e = 7 d + e = 5

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?

Abag of jelly beans contain 13 pink, green, 20 yellow, 10 black, 7 red, and 11 orange jelly beans. approximately what percent of the jelly beans are pink and yellow?

Jane has 5 nickels.john has 3 dimes.jane says she has a greater amount of money.with the information given,is she correct?