Đáp án+Giải thích các bước giải:
`1)`
`a) 15a²b³c : 3a²b`
`= (15 : 3)(a²:a²)(b³:b)c`
`= 5b²c`
`b) -21xy^5z³ : 7xy²z³`
`=(-21 : 7)(x:x)(y^5:y²)(z³:z³)`
`=-3y³`
`c) 2m³n : (-3m²n)`
`= [2:(-3)](m³:m²)(n:n)`
`= -2/3m`
`d) (-1/2a³b^4c^5) : (3/2a²bc^5)`
`= (-1/2 : 3/2)(a³:a²)(b^4:b)(c^5:c^5)`
`= -1/3ab³`
`2)`
`a) 2x^5 : x^n`
`= 2x^(5-n)`
`-> n≤5 -> x = {1;2;3;4;5}`
`b) 5x^(2n)y^4 : 3x^6y^3`
`= (5:3)(x^(2n) : x^6)(y^4:y^3)`
`= 5/3x^(2n-6)y`
`-> 2n≥6 -> n≥12`
`c) 3x^ny^4 : 2x²y^(n-1)`
`= (3:2)(x^n:x²)(y^4:y^(n-1))`
`= 3/2x^(n-2)y^(4-n+1)`
`= 3/2x^(n-2)y^(5-n)`
`-> n ≥ 2 ; n≤5 -> 2≤n≤5 -> n = {2;3;4;5}`
