In triangle ABC, M is the midpoint of side BC and G is the centroid of triangle ABC. A line l passes through G, intersecting line AB at P and line AC at Q, where P=B and Q=C. If [XYZ] denotes the area of triangle XYZ, show that \frac{[BGM]}{[PAG]}\plus{}\frac{[CMG]}{[QGA]}\equal{}\frac32. geometrygeometry proposed