Đáp án:
`a) = -19/5`
`b) = 1`
`c) = 1`
Giải thích các bước giải:
`a) -3/5 × 9/11 + -3/5 × 2/11- 3 1/5`
`= -3/5 × ( 9/11 + 2/11 ) - 3 1/5`
`= -3/5 × 1 - 16/5`
`= -3/5 - 16/5`
`= -19/5`
`b) 7/19 × 8/11 + 7/19 × 3/11 + 12/19`
`= 7/19 × ( 8/11 + 3/11 ) + 12/19`
`= 7/19 × 1 + 12/19`
`= 7/19 + 12/19`
`= 1`
`c) -5/7 × 2/11 + -5/7 × 9/ 11 + 1 5/7`
`= -5/7 × ( 2/11 + 9/11 ) + 12/7`
`= -5/7 × 1 + 12/7`
`= -5/7 + 12/7`
`= 1`