If Jeremy is j then Sam has to be j + 2 since they are consecutive odd integers. It says their product is 783... so
j * (j + 2) = 783
j^2 + 2j = 783
The reason it ISN'T j^2 + 2 is because the parentheses. It's the product of Jeremy and Sam... Sam's age has to be kept together as j+2 and Jeremy (j) has to be multiplied by the whole thing, not just j.