Đáp án:

`a)456/23=(456*32)/(23*32)=14592/736`
`465/32=(465*23)/(32*23)=10695/736`
Vì: `14592/736 > 10695/736`
Vậy: `456/23 > 465/32`

`b)-173/457=(-173*47)/(457*47)=-8131/21479`
`-16/47=(-16*457)/(47*457)=-7312/21479`
Vì: `-8131/21479 < -7312/21479`
Vậy: `-173/457 < -16/47`
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