Solve this: Q.150. If the position vectors of three points are a → - 2 b → + 3 c → , 2 a → + 3 b → - 4 c → a n d - 7 a → + 10 c → , then the three points are (a) collinear (b) non-collinear (c) coplanar (d) None of these Share with your friends Share 2 Aarushi Mishra answered this Let poistion vector of Pp→=a→-2b→+3c→Qq→=2a→+3b→-4c→Rr→=-7a→+10c→Let us first assume that these points are collinear. Then PQR lie in a striaght line.Veector PQ→ must be parallel to QR→ PQ→=q→-p→=2a→+3b→-4c→-a→-2b→+3c→=a→+5b→-7c→ QR→=r→-q→=-7a→+10c→-2a→+3b→-4c→=-9a→-3b→-14c→PQ→ doesn't looks parallel to QR→. Hence we cannot say they are collinear.Also we cannot commenthat they are non-collinear as a→, b→ and c→ might take values such that PQ→ becomes parallel to PR→. Since we dont know a→, b→ and c→ hence we cannot commmentBut we know any three points always lie on a plane. So we can definitely say that they are co-planar. 0 View Full Answer