Answer:
y = x/5 + 12/5
Explanation:
Slope of AC is (6 - 1)/(1 - 2) = -5
slope of the line perpendicular to AC is -1//(-5) = 1/5
the equation of the line perpendicular to AC is y = x/5 + b
the equation of the line passing through B, so 3 = 3/5 + b, b = 12/5
the equation of the line passing through B and perpendicular to AC is y = x/5 + 12/5