450-50540-400678-а786-а = 450 - (50540) - (400678-а)(786-а)= 450 - 27000 - (400678786 - 400678a - 786a + a^2)= 450 - 27000 - (315380428 - 400678a - 786a + a^2)= 450 - 27000 - (315380428 - 118646a + a^2)= 450 - 27000 - 315380428 + 118646a - a^2= -27000 - 315379978 + 118646a - a^2= -342379978 + 118646*a - a^2
Therefore, the final expression is - a^2 + 118646a - 342379978.
450-50540-400678-а786-а = 450 - (50540) - (400678-а)(786-а)
= 450 - 27000 - (400678786 - 400678a - 786a + a^2)
= 450 - 27000 - (315380428 - 400678a - 786a + a^2)
= 450 - 27000 - (315380428 - 118646a + a^2)
= 450 - 27000 - 315380428 + 118646a - a^2
= -27000 - 315379978 + 118646a - a^2
= -342379978 + 118646*a - a^2
Therefore, the final expression is - a^2 + 118646a - 342379978.