Question 263697
125^(x+3)=(5^(2x))/(15625)

a^m*a^n=a^(m+n)

125^x+125^3= 5^2x/ 15625

(5^3)^x +(5^3)^3 = 5^2x/15625

5^3x +5^9=5^2x/(25)^3

5^3x +5^9 = 5^2x / 5^6

5^3x +5^9 = 5^(2x-6)

3x+9=2x-6

x=-15