 Hi and welcome to the session. Let us discuss the following question. The question says, if p having coordinates 2 minus 3 is the midpoint of the joining of a having coordinate 7a and b having coordinates b minus 1, find a and b. Now, begin with the solution. First of all, we should know the section formula. In section formula, coordinates of point p dividing the line segment joining the points a and b, internally in the ratio m1 is to m2 are driven by m1 x2 plus m2 x1 divided by m1 plus m2 divided by 2 plus m2 y1 divided by m1 plus m2. Point of a b, a is having coordinate 7a and b is having coordinates b minus 1. We have to find the value of a and b. Point of a b, therefore it divides a b in the ratio 1 is to 1 and thus it means m1 is equal to 1 and m2 is also equal to 1. Now here, e m2 is equal to 1, x1 is equal to 7, mb is equal to minus 3.