1/a+1/b=9/2(a+b)
所以2a^2-5ab+2b^2=0
所以b/a+a/b=(a+b)/ab=(5/2)/(2/2）=5/2第一步可以写详细点吗1/a+1/b=9/2(a+b)(a+b)/ab=9/2(a+b)2(a+b)^2=9ab2a^2-5ab+2b^2=0