Let's evaluate the domain of 1x3 -x For the expression 1x3 -x to exist, you must check: x3 -x ≠ 0 You can factorize the expression: x3 -x into: x·(x2 -1) Solution found: x ≠ 0 Let's solve in ℝ: x2 -1 ≠ 0 Solution found: x ∈ ℝ \ { -1, 1 } ▶Domain of definition: x ∈ ℝ \ { -1, 0, 1 }