Algebra

I would show all the steps to the problem, but that would be a bit time consuming, so I will highlight the way to go. 

We just have to use the distributive property to get ${x^{3}\left(x^{4}-8x^{3}+17x^{2}-23x+14\right)+x^{2}\left(x^{4}-8x^{3}+17x^{2}-23x+14\right)+x\left(x^{4}-8x^{3}+17x^{2}-23x+14\right)+1\left(x^{4}-8x^{3}+17x^{2}-23x+14\right)}$

Eventually, we get $x^{7}-7x^{6}+10x^{5}-13x^{4}+8x^{2}-9x+14$. 

So the coefficient of x is -9. 

Thanks! :)