a=√(8-x),b=√(3x+4),c=√(x+2).易知,8-x＞0,且x+2＞0,且3x+4＞0.解得:-4/3x=-10.(舍）（2）若a²+c²=b².===>(8-x)+(x+2)=3x+4.===>x=2.(3)若b²+c²=a².===>(3x+4)+(x+2)=8-x.===>x=2/5.综上可知,x=2或x=2/5.