Question

show that a*b =ab+1 is a group for all a,b belongs to rational numbers​

Answer 1

let us consider a and b be rational numbers,

then, $a \times b =$ also a rational no.,

then,

$a \times b + 1 =$ will also be a rational no.,

Therefore,

this contradication proves that,

$a \times b = a \times b + 1$ belongs to rational number groups.