Find $w$, such that $5^65^w=25$.
To solve for $w$, I need to express both sides of the equation in terms of the same base. Then, using the exponent rule $a^ba^c=a^{b+c}$, I can combine the exponents on the left side. This gives me $5^{6+w}=5^2$. Solving for $w$, I get $w=2-6=-4$. 