wuzhuoxihuxing ：(x-4)²-(4x-x)(8-x)=12(x-4)²-3x(8-x)=12x²+16-8x-24x+3x²-12=04x²-32x+4=0x²-8x+1=0x²-8x+16-15=0(x-4)²=15x-4=±√15x=±√15+4∴x1=√15+4,x2=4-√15...