`1)x^12:x^10=x^(12-10)=x^2`
`2)(-y)^7:(-y)^3=(-y)^(7-3)=(-y)^4=y^4`
`3)6x²y³:2xy²`
`=(6:2).(x²:x).(y³:y²)`
`=3xy`
`4)3/4x³y³:(-1/2x²y²)`
`=[3/4:(-1/2)].(x³:x²).(y³:y²)`
`=-3/2xy`
`5)(-2x^5+3x²-4x³):2x²`
`=[(-2x^5):2x²]+(3x²:2x²)+[(-4x³):2x²]`
`=-x³+3/2-2x`
`6)(x³-2x²y+3xy²):(-1/2x)`
`=[x³:(-1/2x)]+[(-2x²y):(-1/2x)]+[3xy²:(-1/2x)]`
`=-2x²+4xy-6y²`
`7)(x²+4xy+4y²):(x+2y)`
`=[x²+2.x.2y+(2y)²]:(x+2y)`
`=(x+2y)²:(x+2y)`
`=x+2y`
`8)(125x³-8):(5x-2)`
`=[(5x)³-2³]:(5x-2)`
`=(5x-2)[(5x)²+5x.2+2²]:(5x-2)`
`=(5x-2)(25x²+10x+4):(5x-2)`
`=25x²+10x+4`
