`1.`\(x^2+2xy+y^2-4=\left(x+y\right)^2-2^2=\left(x+y+2\right)\left(x+y-2\right)\)
`2.`\(3xy^2-12xy+12x=3x\left(y^2-4y+4\right)=3x\left(y-2\right)^2\)
`1)x^2+2xy+y^2-4`
`=(x+y)^2-4`
`=(x+y-2)(x+y+2)`
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`2)3xy^2-12xy+12x`
`=3x(y^2-4y+4)`
`=3x(y-2)^2`
1)(x2+2xy+y2)-4=(x+y)2-4=(x+y-2).(x+y+2)
2)3xy2-12xy+12x=3x.(y2-4y+4)=3x.(y-2)2