Encuentre la integral de f(x, y, z) = x + y + z sobre el segmento de recta que va desde (1, 2, 3) hasta (0, - 1, 1)?

(1) hallemos la ecuación de la recta que pasa por tales puntos<img src="https://tex.z-dn.net/?f=%20%28x%2Cy%2Cz%29%3D%281%2C2%2C3%29%2B%5B%280%2C-1%2C1%29-%281%2C2%2C3%29%5Dr~%2C~%20r%5Cin%20%5Cmathbb%7BR%7D%5C%5C%20%5C%5C%28x%2Cy%2Cz%29%3D%281%2C2%2C3%29-%281%2C3%2C2%29r~%2C~%20r%5Cin%20%5Cmathbb%7BR%7D%5C%5C%20%5C%5C%5Ctext%7BLa%20ecuaci%5C%27on%20del%20segmento...%7D%5C%5C%20%5C%5C%5Cbullet%20%5Ctext%7B%20Note%20que%20con%20%24r%3D0%24%20tenemos%20el%20punto%20de%20partida%20%24%281%2C2%2C3%29%24%20y%20con%20%24r%3D1%24%20%7D%5C%5C%20%5Ctext%7Btenemos%20el%20punto%20final%20%24%280%2C-1%2C1%29%24%20entonces%20%3A%7D%5C%5C%20%5C%5C%5Chspace%2A%7B3cm%7D%5Cphi%28r%29%3D%5Cbegin%7Bcases%7Dx%3D1-r%5C%5Cy%3D2-3r%5C%5Cz%3D3-2r%5Cend%7Bcases%7D~%2C~r%5Cin%20%5B0%2C1%5D%5C%5C%20%5C%5C%20%5C%5C%5Cbullet%20f%28x%2Cy%2Cz%29%3Dx%2By%2Bz%5Cto%20%28f%5Ccirc%20%5Cphi%29%28r%29%3D%20%281-r%29%2B%282-3r%29%2B%283-2r%29%3D6-6r%5C%5C%20%5C%5C%20" />(2) Calculemos la integral <img src="https://tex.z-dn.net/?f=%20%5Cdisplaystyle%5Cint_%7B%5Cgamma%7Df%3D%5Cint_%7B0%7D%5E%7B1%7D6-6r~dr%5C%5C%20%5C%5C%20%5C%5C%5Chspace%7B3cm%7D%5Cboxed%7B%5Cint_%7B%5Cgamma%7Df%3D3%7D%20" />.