(3x+2y)²-(3x-2y)²
=(3x+2y+3x-2y)(3x+2y-3x+2y) (平方差公式)
=6x × 4y
=24xy
(2a+b-c)(2a-b-c)
=(2a-c)²-b²
=4a²-4ac+c²-b²
=4a²-b²+c²-4ac
(3x+2y)²-(3x-2y)²
=(3x+2y+3x-2y)(3x+2y-3x+2y) (平方差公式)
=6x × 4y
=24xy
(2a+b-c)(2a-b-c)
=(2a-c)²-b²
=4a²-4ac+c²-b²
=4a²-b²+c²-4ac