`lim_{x->1}={4x^6-5x^5+x}/{(1-x)^2}`
`=lim_{x->1}{4x^6-4x^5-x^5+x^4-x^4+x^3-x^3+x^2-x^2+x}/(x-1)^2`
`=lim_{x->1}{4x^5(x-1)-x^4(x-1)-x^3(x-1)-x^2(x-1)-x(x-1)}/(x-1)^2`
`=lim_{x->1}{(x-1)(4x^5-x^4-x^3-x^2-x)}/(x-1)^2`
`=lim_{x->1}{(x-1)(4x^5-4x^4+3x^4-3x^3+2x^3-2x^2+x^2-x)}/(x-1)^2`
`=lim_{x->1}{(x-1)[4x^4(x-1)+3x^3(x-1)+2x^2(x-1)+x(x-1)]}/(x-1)^2`
`=lim_{x->1}{(x-1)^2(4x^4+3x^3+2x^2+x)}/(x-1)^2`
`=lim_{x->1}(4x^4+3x^3+2x^2+x)`
`=4.1^4+3.1^3+2.1^2+1=10`