The point slope formula:
[tex]y-y_1=m(x-x_1)\\\\m=\dfrac{y_2-y_1]{x_2-x_1}[/tex]
We have:
[tex](-5,\ 8)\to x_1=-5,\ y_1=8\\(5,\ 4)\to x_2=5,\ y_2=4[/tex]
Substitute:
[tex]m=\dfrac{4-8}{5-(-5)}=\dfrac{-4}{10}=-0.4\\\\y-8=-0.4(x-(-5))\\\\y-8=-0.4(x+5)\ /\text{point slope form}/\\\\y-8=-0.4x-2\ \ \ |+8\\\\y=-0.4x+6\ /\text{slope intercept form}/\\\\y=-0.4x+6\ \ \ \ |+0.4x\\\\0.4x+y=6\ \ \ |\cdot5\\\\2x+5y=30\ /\text{standard form}/[/tex]
