How do you solve 5^d*5^3=5^9?

$d = 6$

Explanation:

We can do it this way - by dividing by ${5}^{3}$:

${5}^{d} \times {5}^{3} = {5}^{9}$

$\frac{{5}^{d} \times {5}^{3}}{5} ^ 3 = {5}^{9} / {5}^{3}$

${5}^{d} = {5}^{9 - 3} = {5}^{6}$

$d = 6$