Find the area of the surface given by z fxy over the region

Solution

let side vectors : (0,0,15) b vector = (3 ,0,21) c vector = (0,3 , 6) ab vector = (3 , 0 , -6) ac vector = (0 ,3 ,-9) area of parallelogram i j k 3 0 -6 0 3 -9 i[18] -j[-27] + k[9] = sqrt[1134] area of other trianlge