Question

$f;A\to B$ defined by $f\left(x\right)=2x+3$ and if $A=\{-2,-1,0,1,2\},B=\{-1,1,3,5,7\}$, then which of function is f?

• A. One - one
• B. Onto
• C. Bijection
• D. Constant

Answer 1

Answer: (C)

Bijection

Clearly putting each of the elements in A as x in f(x) we get the elements of B as the result.

All elements in B are mapped to all elements in A in the same order that they have been mentioned in respective sets. $\Rightarrow onto$

No two x give the same value of f(x). $\Rightarrow one-one$

Hence it is a bijection.