remember
ax+bx=(a+b)x
(xᵃ)(xᵇ)=xᵃ⁺ᵇ
(x+0)=x
so the first few terms can be condensed into (x+0)⁵ or x⁵
the last bit
(x-1)(x-4)(x-2)
multiply seperately
(x-1)(x-4)=x^2-x-4x+4=x²-5x+4
now we do
(x²-5x+4)(x-2)=x³-5x²+4x-2x²+10x-8=x³-7x²+14x-8
in all
(x⁵)(x³-7x²+14x-8) or x⁸-7x⁷+14x⁶-8x⁵