Using the rule

`d/(dx)(cy)=c(d)/(dx)(y)`

we can take the -7 out the front:

`d/(dx)(-7x^6)=-7d/(dx)(x^6)`

And

`d/(dx)x^n=nx^(n-1)`

gives us:

`-7d/(dx)(x^6)=-7xx6x^5=-42x^5`

Note: We can do this in one step:

`(dy)/(dx)=-42x^5`

We can write: `(dy)/(dx)=-42x^5` OR `y'=-42x^5`. They mean the same thing.

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