${8}^{-7+7} \times {10}^{4} \times {10}^{-4}$
Multiply the terms with the same base by adding their exponents${8}^{-7+7} \times {10}^{4-4}$
The sum of two opposites equals $0$${8}^{0} \times {10}^{4-4}$
The sum of two opposites equals $0$${8}^{0} \times {10}^{0}$
Any non-zero expression raised to the power of $0$ equals $1$$1 \times {10}^{0}$
Any non-zero expression raised to the power of $0$ equals $1$$1 \times 1$
Any expression multiplied by $1$ remains the same$1$