prove the area of a quadrilateral having diagonals given by d1vector d2vector is |d1vector x d2vector| /2

solve for X and Y if 10 upon X + Y + 2 upon x-y=4 and15 upon X + Y - 15 upon x minus y = - 2

Exercise 7.5 ncert class 12

Show that the points whose position vectors are i ̂ +2j ̂+3k ̂,-2i ̂ +3j ̂+5k ̂ and 7 i ̂ -k ̂ are collinear

The questions which will definetly come in exams