Let the linear L equation be: x/a+y/b= 1 (intercept formula).

∵

The straight line passes through point P(2, 1).

∴

2/a+ 1/b= 1。

∴

ab=a+2b。

According to the mean inequality formula (x+y≧2√xy), if and only if x=y, take the equal sign.

), available:

∴

ab=a+2b≧2*√(2ab)。

∴(ab)≧8ab.

∵ab≠0，

∴ab≧8.

∴⊿aob∴⊿ Minimum area

=( 1/2)ab

=4.

At this time a=2b,

That is ab=2b=8.

∴

a=4，

b=2。

∴ The equation of the straight line L is: x/4+y/2= 1.