因式分解 (2X+1)²—(5X-4)²=(2x+1+5x-4)(2x+1-5x+4)=(7x-3)(-3x+5)=-(7x-3)(3x-5);第二题（5X²+3Y²）²—（3X²+5Y²）² =[(5x²+3y²)+(3x²+5y²)][(5x...