Find the value of N.
n = ???

Let m = slope = -4/5
P(x,y) = P(5,10)

Slope-intercept form for the equation of a line:
y=mx+c

Plug m= -4/5 into the slope-intercept formula
y = -4/5x + c

Plug P(5,10) into point-slope formula
y = -4/5x + c
10 = -4/5(5) + c
10 = -4 + c
substract -4 from both sides,
10 - (-4) = -4 - (-4) + c
14 = c

So, the equation is y = -4/5x + 14