Trình bày lời giải:
Bài `1.`
`a)`
`1 1/3-0,75.(2/3)^2`
`=4/3-0,75 . 4/9`
`=4/3-3/4 . 4/9`
`=4/3-1/3`
`=3/3`
`=1`
`b)`
`(-2/7+1/5):9/35+(4/5-5/7):9/35`
`=(-2/7+1/5). 35/9+(4/5-5/7). 35/9`
`=35/9.(-2/7+1/5+4/5-5/7)`
`=35/9.(-7/7+5/5)`
`=35/9 . (-1+1)`
`=35/9 .0`
`=0`
`c)`
`5/12:(1 1/2-2 1/3)-|-1/2|`
`=5/12:(1+1/2-2-1/3)-1/2`
`=5/12:(-1+1/2-1/3)-1/2`
`=5/12:(-2/2+1/2-1/3)-1/2`
`=5/12:(-1/2-1/3)-1/2`
`=5/12:(-3/6-2/6)-1/2`
`=5/12 : (-5)/6-1/2`
`=5/12 . (-6)/5-1/2`
`=-1/2-1/2`
`=-2/2`
`=-1`
`d)`
`(2^30 . 9^8)/(6^12 . 8^6)`
`=(2^30 . (3^2)^8)/((2.3)^12 . (2^3)^6)`
`=(2^30 . 3^16)/(2^12 . 3^12 . 2^18)`
`=(2^30 . 3^16)/(2^30 . 3^12)`
`=(1. 3^4)/(1.1)`
`=81`
