Answers

2014-10-02T00:46:05+08:00
(3x²y+4xy²-5)²
this is the pattern        (a+b-c)² = a²+b²+c²+2ab-2ac-2bc
(3x²y)²+(4xy²)²+(-5)² +( 2 . 3x²y . 4xy²)-(2 . 3x²y . 5)-(2 . 4xy² . 5)
 =    9x⁴y²+ 16x²2y⁴4+ 24x³y³- 30x²y -40xy²
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