for r1, r2, x0, x1, x2, x3, x4, x5 being Real
for f1, f2 being Function of REAL,REAL holds [!((r1 (#) f1) + (r2 (#) f2)),x0,x1,x2,x3,x4,x5!] = (r1 * [!f1,x0,x1,x2,x3,x4,x5!]) + (r2 * [!f2,x0,x1,x2,x3,x4,x5!])