Using the one point format, for a slope m, and point (x₁, y₁)
y - y₁ = m(x - x₁)
Slope, m = (4/5) point (x₁, y₁) = (0, 1), x₁ = 0, y₁ = 1
y - 1 = (4/5)*(x - 0)
y - 1 = (4/5)x
y - 1 = 4x / 5
5*(y - 1) = 4x
5*y - 5*1 = 4x
5y - 5 = 4x
5y = 4x + 5 is the equation of the line.