Assuming that that is a rectangle with a corner missing, first find the area of the whole rectangle (including the cutout piece), then subtract the cutout piece's area from the whole area of the rectangle.
because the base of the rectangle is 9 and the height 7, 9 x 7 = 63 which is the total area of the rectangle
next subtract the area of the missing corner/triangle, because it's a rectangle and the bases are the same length 9= 7+ 2, therefore the length of the missing triangle is 2, to get the area of the triangle multiply 2 x 7 =14 then divide that by 2 = 7 in
To get the final area of the rectangle with the corner missing, subtract the area of the missing piece from the area of the full rectangle, 63-7 = 56 in.
This is only correct if this shape is a rectangle.