In Cartesian coordinate system, the line L1 passes through (2, 3) and (- 1, - 3), the line L2 passes through the origin o, and intersects with the line L1 at the point P (- 2, a). (1) find the value of a; (2) (- 2, a) what kind of solution of binary linear equations can be seen? (3) Let the line L1 and the y-axis intersect at point A. can you find the area of △ apo?

In Cartesian coordinate system, the line L1 passes through (2, 3) and (- 1, - 3), the line L2 passes through the origin o, and intersects with the line L1 at the point P (- 2, a). (1) find the value of a; (2) (- 2, a) what kind of solution of binary linear equations can be seen? (3) Let the line L1 and the y-axis intersect at point A. can you find the area of △ apo?

(1) Through (2, 3) and (- 1, - 3), the analytic formula of line L1 is y = 2x-1, substituting P (- 2, a) into y = 2x-1 to get a = 2 × (- 2) - 1 = - 5; (2) let the analytic formula of L2 be y = KX, substituting P (- 2, - 5) into - 5 = - 2K to get k = 5