`a)36x²-(x²+9)²`
`=(6x)²-(x²+9)²`
`=(6x-x²-9)(6x+x²+9)`
`=-(x²-6x+9)(x²+6x+9)`
`=-(x-3)²(x+3)²`
`b)2x²-3x-2`
`=2x²-4x+x-2`
`=2x(x-2)+(x-2)`
`=(x-2)(2x+1)`
`c)x³+x²-2x-2`
`=x²(x+1)-2(x+1)`
`=(x+1)(x²-2)`
`=(x+1)[x²-(`$\sqrt[]{2}$ `)^2]`
`=(x+1)(x+`$\sqrt[]{2}$ `)(x-`$\sqrt[]{2}$ `)`
`d)4x²-9-4xy+y²`
`=(4x²-4xy+y²)-9`
`=[(2x)²-2.2x.y+y²]-3²`
`=(2x-y)²-3²`
`=(2x-y+3)(2x-y-3)`
`e)3x²y-6xy²+3y²`
`=3y(x²-2xy+y)`
`f)x³-2x²y-4x+8y`
`=x²(x-2y)-4(x-2y)`
`=(x-2y)(x²-4)`
`=(x-2y)(x+2)(x-2)`
`g)x²-2xy+y²-x+y`
`=(x²-2xy+y²)-(x-y)`
`=(x-y)²-(x-y)`
`=(x-y)(x-y-1)`
`h)7x²-8x+1`
`=7x²-7x-x+1`
`=7x(x-1)-(x-1)`
`=(x-1)(7x-1)`
