Find an equation for the line which passes through (-1,4) and is perpendicular to the line containing (0,1) and (4,5)

line containing (0,1) and (4,5)
slope = (5-1)/(4-0) = 4/4=1
perpendicular lines, so slope will be opposite and reciprocal
so slope = -1

passes through (-1,4) 
y = mx + b
4  = -1(-1) + b
4 = 1 + b
b = 3

equation
y = -x + 3

hope it helps