Prove : If $a < b$ then $-b < -a$
My proof :
$a + (-b) < b + (-b) $
$a - b < 0$
$a - b + (-a) < 0 + (-a)$
$a + (-a) -b < -a$
$-b < -a$
Is my proof correct?
Prove : If $a < b$ then $-b < -a$
My proof :
$a + (-b) < b + (-b) $
$a - b < 0$
$a - b + (-a) < 0 + (-a)$
$a + (-a) -b < -a$
$-b < -a$
Is my proof correct?
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Direct alternative proof.
$a < b $
$-a + a - b < -a + b - b $
$-b < -a$