Odpowiedzi

2009-12-02T16:29:09+01:00
2(x²-y²)-3(x²-4xy+4y²) = 2x² - 2y² - 3x² + 12xy -12y² = -x²+12xy-14y²
2009-12-02T16:31:06+01:00
Wzory skróconego mnożenia:
(a+b)(a-b) = a²-b²
(a+b)² = a²+2ab+b²
(a-b)² = a²-2ab+b²

2(x-y)(x+y)-3(x-2y)² = 2(x²-y²)-3(x²-4xy+4y²) = 2x²-2y²-3x²+12xy-12y² = -x²+12xy-14y²
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2009-12-02T16:45:14+01:00
2(x-y)(x+y)-3(x-2y)² =2(xkwadrat+xy-xy-ykwadrat)-3(xkwadrat+4ykwadrat-4xy)=2xkwadrat-2ykwadrat - 3xkwadrat+4ykwadrat-4xy= -xkwadrat+2ykwadrat-4xy