Question

A line passes through (1,1) , (-2,4) , and (6,n) . Find the value of n.

Answer 1

$General\ formula\ for\ line:\\y=ax+b\\\\ Passes\ through\ (1,1)\ (-2,4)\\\\\left \{ {{1=1a+b\ |\cdot2} \atop {4=-2a+b}} \right. \\\\ \left \{ {{2=2a+2b} \atop {4=-2a+b}} \right. \\+-----\\\\6=3b\ \ |:3\\b=2\\\\1=a+2\\1-2=a\\a=-1\\\\y=-x+2\\\\Passes\ through\ (6,n):\\\\n=-6+2\\\\\boxed{n=-4}$