WAEC Mathematics 2018 Paper

Concept:A fraction is defined only when its denominator is not $0$.If the denominator is $0$, the expression becomes undefined.Explanation:The given expression is $\frac{x-5}{x(x-1)}$.Its denominator is $x(x-1)$.For the expression to be defined, the denominator must not equal $0$.So set the denominator equal to $0$ to find the values that must be rejected:$x(x-1)=0$.Therefore, $x=0$ or $x-1=0$.This gives $x=0$ or $x=1$.At these values, the expression is not defined.Hence, it is defined for all real numbers except $0$ and $1$.Answer:The expression becomes undefined for $x=0$ or $x=1$.So the correct option is D. $0$ or $1$.