Toán Lớp 8: 1) 27+b^3
2) a^2 -64
3) 8x^3-y^3
4) 25y^3-(1+4y)^2
5) (x+2)^2-(y+5)^2
6) (3-x)-(y-1)^2
nhanh nhất có thể đc ko ạ !
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Toán Lớp 8: 1) 27+b^3
2) a^2 -64
3) 8x^3-y^3
4) 25y^3-(1+4y)^2
5) (x+2)^2-(y+5)^2
6) (3-x)-(y-1)^2
nhanh nhất có thể đc ko ạ !
Comments ( 2 )
27+b^3
=3^3+b^3
=(3+b)(9-3b+b^2)
2,
a^2 -64
=a^2-8^2
=(a-8)(a+8)
3,
8x^3-y^3
=(2x)^3-y^3
=(2x-y)(4x^2+2xy+y^2)
4, 25y^3-(1+4y)^2
=25y^3-(1+8y+16y^2)
=25y^3-1-8y-16y^2
5, (x+2)^2-(y+5)^2
=(x+2+y+5)(x+2-y-5)
=(x+y+7)(x+y-3)
6, (3-x)-(y-1)^2
=3-x-(y^2-2y+1)
=3-x-y^2+2y-1