After the release of radioactive material into the atmosphere from a nuclear power plant in a country in 1991, the hay in that country was contaminated by a radioactive isotope (half-life 8 days). If it is safe to feed the hay to cows when 15% of the radioactive isotope remains, how long did the farmers need to wait to use this hay? The farmers needed to wait approximately _ days for it to be safe to feed the hay to the cows.

Tomas is making trail mix using granola and walnuts. he can spend a total of $12 on the ingredients. he buys 3 pounds of granola that costs $2.00 per pound. the walnuts cost $6 per pound. he uses the equation to represent the total cost, where x represents the number of pounds of granola and y represents the number of pounds of walnuts. he solves the equation for y, the number of pounds of walnuts he can buy. answer- b tomas added 6 to both sides of the equation instead of subtracting 6. just took the test

If c(x) = 4x – 2 and d(x) = x2 + 5x, what is (cxd)(x)

This is so hard and it’s for a test