what is each expression written using each base only once?Please help! I don't understand this. I need the answers to all parts for number 2

To solve these problems, we just have to add the exponents
[tex]\begin{gathered} (7.57)^{-5}(7.57)^5=(7.57)^{-5+5}=(7.57)^0=1 \\ x^3x^7=x^{3+7}=x^{10} \\ (-5)^5(-5)^6=(-5)^{5+6}=(-5)^{11} \end{gathered}[/tex]