Pleas help me with this exercises(this is not a homework): Determine whether the points lie on a straight line. a) A(5,1,3), B(7,9,-1), C(1,-15,11) b) K(0,3,-4) L(1,2,-2), M(3,0,1) Should I draw the graph, then find the slopes? Or is there any other way to approach? Pleas help! By the way, I got straight A's for Calc I,II. and every body keep telling me that Calc III is easier compare to Calc II. but, I feel it's so hard, and I don't know what to do. can some one give me some advice?thanks.