Q7 of 107 Page 10

In each of the following cases, state whether the function is one-one, onto or bijective. Justify your answer.

f : R → R defined by f (x) = 3 – 4x

It is given that f : R → R defined by f (x) = 3 – 4x

Let x1, x2ϵ R such that f(x1) = f(x2)


⇒ 3 – 4x1 = 3 – 4x2


⇒ -4x1 = -4x2


⇒ x1 = x2


⇒ f is one- one


For any real number (y) in R, there exist in R such that



⇒ f is onto.


Therefore, function f is bijective.


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