Alex needs to revise his conjecture because the function f(x) is only greater for limited domain since it is a linear function. The function g(x) becomes greater when the value of domain is greater than or equal to 9. In such case,

\(\displaystyle{f{{\left({x}\right)}}}{>}{g{{\left({x}\right)}}}\ {w}{h}{e}{n}\ {1}\le{x}{<}{9}\)

\(\displaystyle{g{{\left({x}\right)}}}{>}{f{{\left({x}\right)}}}\ {w}{h}{e}{n}\ {x}\Rightarrow{9}\)