Solving $8^{x-1}=16$ using the laws of exponents gives $x$ equal to:

1. Rewrite both sides to a common base of 2: $8=2^3$ and $16=2^4$. 2. The left side becomes $2^{3(x-1)}$ and the right side $2^{4}$. 3. With equal bases the exponents must match: $3(x-1)=4$. 4. Expanding gives $3x-3=4$, so $3x=7$. 5. Therefore $x=\dfrac73$. Failing to bring both sides to the same base is what blocked most candidates here. _Source: NECTA CSEE 2022 Basic Mathematics 041, Question 2: Exponents, Radicals and Logarithms_