Question

找规律:3/2+2/3=(3^2+2^2)/2×3；4/3+3/4=(4^2+3^2)/3×4；已知a+b=5,ab+=4，求a/b+b/a的值，谢谢！

要步骤！谢谢！

Answer 1

由上叙规律知：
a/b+b/a=(a^2+b^2)/ab=[(a+b)^2-2ab]/ab
由已知a+b=5,ab=4得
[(a+b)^2-2ab]/ab
=[(5)^2-2×4]/4
=17/4

Answer 2

a/b+b/a
=(a^2+b^2)/ab
=[(a+b)^2-2ab]/ab
=[5^2-2*4]/4
=17/4