49（x-3)²=16(x+6)²49(x-3)²-16(x+6)²=0[7(x-3)]²-[4(x+6]²=0(7x-21)²-(4x+24)²=0(7x-21+4x+24)(7x-21-4x-24)=0(11x+3)(3x-45)=0则 11x+3=0 或3x-45=0解得 x=-11/3 或x=15...