What is the number at the end of an isotopes name? Atomic number neutron number mass number electron

Write the expression in complete factored form. 5n_(c - 3) - n(c - 3) =

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.

Ineed no it anyone can see this