Toán Lớp 8: a, $x^{3}$ + 8$y^{3}$
b, $x^{2}$ – 6$x$ + 8
c, $x^{8}$ + 16
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Toán Lớp 8: a, $x^{3}$ + 8$y^{3}$
b, $x^{2}$ – 6$x$ + 8
c, $x^{8}$ + 16
Comments ( 2 )
=x^3+(2y)^3
=(x+2y)[x^2-x(2y)+(2y)^2]
=(x+2y)[x^2-2xy+4y^2]
b)x^2-6x+8
=(x^2-2x)-(4x-8)
=x(x-2)-4(x-2)
=(x-2)9x-4)
c)x^8+16
=(x^4)^2+2.4.x^4+4^2-8x^4
=(x^4+4)^2-(sqrt8x^2)^2
=(x^4-sqrt8x^2+4)(x^4+sqrt8x^2+4)