What combination of protons and neutrons would make carbon 14 be radioactive?

6 protons 8 neutrons
7 protons 7 neutrons
8 protons 6 neutrons
14 protons 0 neutrons

If m 17 27 90 63 ** picture is attached

Idont understand math at all! : o( use this scenario to answer the remaining questions: brenton purchased a new bedroom set for $4,500.00. he lives in arizona and pays a 8.75% sales tax. if he made a 50% down payment and financed the rest, what amount did he finance? what is the total sales tax brenton will pay? enter your answer in currency format, round to the nearest cent. what was brenton's total amount financed? enter your answer in currency format, round to the nearest cent.

Someone me what is the area of this figure? 18m 18m 8m 16m