(lg2)³+3lg2*lg5+(lg5)³等于多少

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(lg2)³+3lg2*lg5+(lg5)³等于多少(lg2)³+3lg2*lg5+(lg5)³等于多少(lg2)³+3lg2*lg5+(lg5)&s

(lg2)³+3lg2*lg5+(lg5)³等于多少
(lg2)³+3lg2*lg5+(lg5)³等于多少

(lg2)³+3lg2*lg5+(lg5)³等于多少
(lg2)³+(lg5)³+3lg2*lg5
=(lg2+lg5)[(lg2)²-lg2*lg5+(lg5)²]+3lg2*lg5 (这步是用立方和公式)
=(lg2)²-lg2*lg5+(lg5)²+3lg2*lg5
=(lg2)²+2lg2*lg5+(lg5)²
=(lg2+lg5)²
=1