g) x2-2xy+y2-4=( x2-2xy+y2)-22=*(x-y)2-22=(x-y-2)(x-y+2)
h) x2-y2-2yz-z2=x2-(y2+2yz+z2)=x2-(y+z)2=(x-y-z)(x+y+z)
i) 3a2-6ab+3b2-12c2=3(a2-2ab+b2-4c2)=3\(\left[\left(a^2-2ab+b^2\right)-4c^2\right]\)\(=3\left[\left(a-b\right)^2-\left(2c\right)^2\right]\)\(=3\left(a-b-2c\right)\left(a-b+2c\right)\)
j) x2-2xy+y2-m2+2mn-n2=(x2-2xy+y2)-(m2-2mn+n2)=(x-y)2-(m-n)2=(x-y-m+n)(x-y+m-n)
k) a2-10a+25-y2-4yz-4z2= (a2-10a+25)-(y2-4yz-4z2)=(a-5)2-(y-2z)2=(a-5-y+2z)(a-5+y-2z)
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