\(\frac{x}{a} + \frac{y}{b} = 1 \)
Slope of line = [ -5 - 4 ] / [ -1 - 5 ] = -9/-6 = 3/2
Equation of line y = (3/2)(x - 5) + 4
y = (3/2)x - 7/2 multiply through by -(2/7)
-(2/7)y = - (3/7)x + 1
(3/7)x - (2/7)y = 1 and we can write
x/ (7/3) + y / (-7/2) = 1
a = (7/3)