Simplify the following using laws of exponents.

$2^{3a+7}\times 2^{7a+3}$

Simplify the following using laws of exponents.

${\left(\frac{2}{3}\right)}^5$

Simplify the following using laws of exponents.

$\frac{9^7}{9^{15}}$

Express $\frac{{\left(-6\right)}^5}{{\left(-6\right)}^9}$ in positive exponential form using laws of exponents.

Simplify the following using laws of exponents.

${\left(-6^4\right)}^4$

Simplify the following using laws of exponents.

$a^x\times a^y\times a^z$