In beta decay one neutron disappears and one proton is created. So the atomic number increases by 1. The mass number always remains the same in beta decay, because it is the sum of protons plus neutrons.

For question 6, the initial nucleus is neptunium. We find from the Nuclear Table that the atomic number of neptunium is 93. It has 93 protons and 146 neutrons (239 - 93). Its symbol is ²³⁹₉₃Np. Hence the product nucleus has atomic number 94 and mass number 239. From the Table you find that plutonium is the element with mass number 94; its chemical symbol is Pu. So the products of the decay are ²³⁹₉₄Pu plus an electron.

For question 8, the initial nucleus is carbon, atomic number 6. So the final nucleus has atomic number 7; it is nitrogen. So the final nucleus is ¹⁴₇N, which is the common isotope of nitrogen.