Acertain element has a half life of 4.5 billion years. a. you find a rock containing a mixture of the element and lead. you determine that 60% of the original element remains; the other 40% decayed into lead. how old is the rock? b. analysis of another rock shows that it contains 5% of its original element; the other 95% decayed into lead. how old is the rock?

Arianna is buying plants for her garden. she buys 15 flowering plants for $96. pink flowering plants sell for $8, and purple flowering plants sell for $5. how many pink flowering plants did arianna buy? i figured out the answer! the answer is 7. 8x +5y = 96 plug in 7 for x 8 (7) + 5y = 96 56 + 5y = 96 subtract 56 from both sides 5y/y = 40/5 y = 8 she bought 7 pink and 8 purple plants

At the beginning of year 1, carlos invests $600 at an annual compound interest rate of 4%. he makes no deposits to or withdrawals from the account. which explicit formula can be used to find the account's balance at the beginning of year 5? what is, the balance?

Simplify. 3(4+4x) (type your answer in with no spaces)