计算(5a-4b)²-2(5a-4b)(3a-2b)
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计算(5a-4b)²-2(5a-4b)(3a-2b)
计算(5a-4b)²-2(5a-4b)(3a-2b)
计算(5a-4b)²-2(5a-4b)(3a-2b)
(5a-4b)²-2(5a-4b)(3a-2b)
=25a²-40ab+16b²-30a²+44ab-16b²
=-5a²+4ab
(5a-4b)²-2(5a-4b)(3a-2b)
=(5a-4b)【(5a-4b)-2(3a-2b)]
=(5a-4b)(-a)
=-5a^2-4ab
(5a-4b)²-2(5a-4b)(3a-2b)
=25a²-40ab+16b²-30a²+44ab-16b²
=-5a²+4ab