Substituting y=-8/x gives m=4 and n=4.

So a (-2,4), b (4 4,2)

Substitute the coordinates of a and b into y = kx+b.

-2k+b=4

4k+b=-2

The solution is k =- 1 and b = 2.

So the main resolution function is y=-x+2.

2) The area of triangle AOB = 1/2*(4+2)*2=6.