Đáp án :
`text{Câu 1}`
$a/$ `210 + (-215) - (4^2 - 1^{20}) + (-2018)^0`
`= 210 - 215 - (16 - 1) + 1`
`= 210 - 215 - 15 + 1`
`= -5 - 15 + 1`
`= -20 + 1`
`= -19`
$b/$ `0,8 . (5/6 - 75%) + (-1/3)^2`
`= 0,8 . 1/12 + 1/9`
`= 1/15 + 1/9`
`= 8/45`
`text{Câu 2}`
`a) 3/4x - 4 1/4 = 0,75`
`-> 3/4x - 17/4 = 0,75`
`-> 3/4x = 5`
`-> x = 20/3`
$b/$ `7/12 - (x + 7/10) : 6/5 = (-5)/4`
`-> (x + 7/10) : 6/5 = 11/6`
`-> x + 7/10 = 11/5`
`-> x = 3/2`
