X³+5x²+3x+9 x四次方—7x²+1

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X³+5x²+3x+9 x四次方—7x²+1
X³+5x²+3x+9 x四次方—7x²+1

X³+5x²+3x+9 x四次方—7x²+1
X³+5x²+3x-9
=x(x^2+4x+3)+x^2-9
=x(x+3)(x+1)+(x+3)(x-3)
=(x+3)[x(x+1)+x-3]
=(x+3)[x^2+2x-3]
=(x+3)^2(x-1)
x四次方—7x²+1
=(x^2-1)^2-5x^2
=(x^2-1+√5x)(x^2-1-√5x) .