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The function $f:\mathbb{R}\to\mathbb{R}$ given by $f(x) = 2x + 3$ is:
Aonto but not one-one
Bneither one-one nor onto
Cone-one but not onto
Dboth one-one and onto (bijective)
Answer & Solution
Correct answer: D. both one-one and onto (bijective)
A non-constant linear map f(x)=2x+3 on ℝ is strictly increasing (one-one) and covers all reals (onto) — hence bijective.
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