X-(2-x)=4(x-5), x=-6
((X - (2 - x)) - 4 (x - 5) x, x^2-1, ((X - (2 - x)) - 4 (x - 5) x){d/dx ((X - (2 - x)) - 4 (x - 5) x), ((X - (2 - x)) - 4 (x - 5) x)}