The propagation of uncertainty formula for the equation y = mx + b is given by ∆y = √((∆m * x)^2 + (∆x * m)^2 + (∆b)^2), where ∆m is the uncertainty on m, ∆x is the uncertainty on x, and ∆b is the uncertainty on b. If m = -19 ± 0.8, x = -0.9 ± 0.1, and b = 2 ± 0.3, then what is the uncertainty on y?