Câu `7:`
`2015 - (4 5/9 + x - 7 7/18) : 15 2/3 = 2014`
`=> 2015 - (41/9 + x - 133/18) : 47/3 = 2014`
`=> (41/9 + x - 133/18) : 47/3 = 2015 - 2014`
`=> (41/9 + x - 133/18) . 3/47 = 1`
`=> 41/9 + x - 133/18 = 1 : 3/47`
`=> 41/9 + x - 133/18 = 47/3`
`=> 41/9 + x = 47/3 + 133/18`
`=> 41/9 + x = 415/18`
`=> x = 415/18 - 41/9`
`=> x = 37/2`
Vậy `x = 37/2`
Câu `8:`
`2/3x - 70 10/11 : (131313/151515 + 131313/353535 + 131313/636363 + 131313/999999 ) = -5`
`=> 2/3x - 780/11 : (13/15 + 13/35 + 13/63 + 13/99) = -5`
`=> 2/3x - 780/11 : 52/33 = -5`
`=> 2/3x - 45 = -5`
`=> 2/3x = 40`
`=> x = 60`
Vậy `x = 60`