Question

a^2+3a=7,b^2+3b=7,则b/a=a/b=

Answer 1

a^2+3a=7,b^2+3b=7,则b/a+a/b=

把a^2+3a=b^2+3b

所以（a-b）（b+a+3）=0

当a-b=0或（b+a+3）=0

得a=b或b+a=-3

1）当a=b时 b/a+a/b=2

2）b+a=-3转化b=-3-a

b/a+a/b=(a^2+b^2)/ab

=(14-3(a+b))/ab =23ab

设23ab=M,b+a=-3

B*-4AC=9-4*23M>或等于0

M