So the straight line Y=X/2+B

Substitution point (-4, -3)

-3=-4/2+B

B=- 1

The linear expression is Y=X/2- 1.

Because the value of b is-1, the coordinate of point b (0,-1), OB= 1.

Substitute Y=0, X/2- 1=0, X=2.

So the coordinate (2,0) of point A, OA = 2.

S△AOB= 1/2×OA×OB= 1