`y=x^4-9x^2-5x`

So

`(dy)/(dx)=4x^3-18x-5`

At the point where x = 3, the derivative has value:

`{: ((dy)/(dx)|_(x\ =\ 3),=4(3)^3-18(3)-5),(,=4xx27-18xx3-5),(,=49) :}`

This means that the slope of the curve `y=x^4-9x^2-5x` at `x= 3` is `49`.