(1)原式=(2/3x)²-y²=4/9x²-y²(2)原式=(2a+3b)(2a-3b)=(2a)²-(3b)²=4a²-9b²(3)原式=(-5+2b)(-5-2b)=(-5)²-(2b)²=25-4b²(4)原式=(2a)²+2×2a×5b+(5b)...
(1)原式=(2/3x)²-y²=4/9x²-y²(2)原式=(2a+3b)(2a-3b)=(2a)²-(3b)²=4a²-9b²(3)原式=(-5+2b)(-5-2b)=(-5)²-(2b)²=25-4b²(4)原式=(2a)²+2×2a×5b+(5b)...