Solve equation for y.
5x - y = 3
-y = -5x + 3
y = (-5x + 3)/(-1)
y = 5x - 3
The slope for this equation is 5.
The slope of the equation we want is the negative reciprocal of 5.
Let m = slope of equation we want.
m = -1/5
We are given the point (10,4).
Plug both into the point-slope formula.
y - 4 = (-1/5)(x - 10)
y - 4 = (-1/5)x + 2
y = (-1/5)x + 2 + 4
The equation we want is
y = (-1/5)x + 6
Did you follow?