x^2-a(3x+4a-20b)+b(5x-24b)=0 整理,得x^2-3ax-4a^2+20ab+5bx-24b^2=0x^2-(3a-5b)x-4(a^2-5ab+6b^2)=0x^2+(5b-3a)x+(8b-4a)(a-3b)=0(x+8b-4a)(x+a-3b)=0x=4a-8b或x=3b-a