Let f : R → R be defined as f(x) = 3x. Choose the correct answer.

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KollegeApply · Accepted Answer

f is one-one onto. Explanation: f : R → R is defined as f(x) = 3x. Let x, y ∈ R such that f(x) = f(y). ⇒ 3x = 3y ⇒ x = y ∴ f is one-one. Also, for any real number (y) in co-domain R, there exists y/3 in R such that f(y/3) = 3(y/3) = y. ∴ f is onto. Hence, function f is one-one and onto.

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