This part of the plane lies above a triangle with boundaries
and
along the coordinate axes, as well as the line

When
, we have
. So this triangle is the set

Also, when
, we have
. So the triangle has length 3 and width 5, hence area 1/2•3•5 = 15/2.
Let
. Then the area of the plane over
is

We have



since the integral

is exactly the area of
, 15/2.
9/3= 3 ampere.. that would be the aswer