Đáp án+Giải thích các bước giải:
a) `A = (5/9 - 3/7 + 3 2/5) + (17/7 - 14/9)`
`A = 5/9 - 3/7 + 17/5 + 17/7 - 14/9`
`A = (5/9 - 14/9) + (17/7 - 3/7) + 17/5`
`A = 1 - 1 + 17/5`
`A = 0 + 17/5`
`A = 17/5`
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b) `B = 6/13 * 3/11 + 7/11 * 6/13 - 21/11 : 13/6`
`B = 6/13 * 3/11 + 7/11 * 6/13 - 21/11 * 6/13`
`B = 6/13 * (3/11 + 7/11 - 21/11)`
`B = 6/13 * (-1)`
`B = -6/13`
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c) `C = 25% * |(-1)/4| : |1/2 : 1/3| + 2021^0`
`C = 1/4 * 1/4 : 1/6 + 1`
`C = 3/8 + 1`
`C = 11/8`
