This Question came up in a test i did today
What i did was multiply out the first two brackets
X² + 5x + 6
then i tried
X³ + 5x then i get confused since i dont know what to multiply 6 by
X² + 5x² i can also work this bit out but i have no idea whats next.
So X³+X²+5x²+5x is what i got so far which can be simplified to X³+5X to the power of 4 + 5x