因式分解---

./303^2-297^2
=./(303-297)(303+297)
=./6(600)
=./3600
=60

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1.726^2-1.724^2
=(1.726-1.724)(1.726+1.724)
=0.002(3.45)
=0.0079

81u^4-16v^4
=(9u^2-4v^2)(9u^2+4v^2)
=(3u-2v)(3u+2v)(9u^2+4v^2)

(e+f)^2+8(e+f)+16
=(e+f)^2+2(4)(e+f)+(4)^2
=(e+f+4)^2

m^2-n^2+8n-16
=m^2-(n^2-8n+16)
=m^2-(n-4)^2
=(m-n+4)(m+n-4)

p^2-6pq+9q^2-r^2+4rs-4s^2
=[p^2-2p(3q)+(3q)^2] - [r^2-2r(2s)+(2s)^2]
=(p-3q)^2 - (r-2s)^2
=(p-3q-r+2s)(p-3q+r-2s)

y^6-1
=(y^3-1)(y^3+1)
=(y-1)(y^2+y+1)(y+1)(y^2-y+1)
=(y-1)(y+1)(y^2-y+1)(y^2+y+1)

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p^2-6pq+9q^2
=p^2-2p(3q)+(3q)^2
=(p-3q)^2

a^2-3a-4
=(a-4)(a+1)

x^2-6xy+9y^2-3(x-3y)-4
=(x-3y)^2-3(x-3y)-4
=(x-3y-4)(x-3y+1)