Step 1 :\(\log x+\log (x-9)=1\)
Step 2 :Using the properties of logarithms, rewrite the equation as \(\log [x \cdot (x-9)] = 1\)
Step 3 :Rewrite the equation in exponential form to get \(x \cdot (x-9) = 10\)
Step 4 :This is a quadratic equation, which can be written as \(x^2 - 9x - 10 = 0\)
Step 5 :Factor the equation to get \((x - 10)(x + 1) = 0\)
Step 6 :Setting each factor equal to zero gives the solutions x = 10 and x = -1
Step 7 :Check these solutions in the original logarithmic equation
Step 8 :Substituting x = 10 into the original equation, we get \(\log 10 + \log (10 - 9) = 1 + 0 = 1\), so x = 10 is a valid solution
Step 9 :Substituting x = -1 into the original equation, we get \(\log (-1) + \log (-1 - 9)\), since the logarithm of a negative number is undefined, x = -1 is not a valid solution
Step 10 :Therefore, the solution set is \(\boxed{10}\)