Help explain how to do this question please

4- (-6n - 7)

there is an invisable 1 between the - sign and the bracket. And if it makes it any easier you can add a + in front of the - sign.  Like this:

=4+    -1(-6n-7)

=4+     -1*-6n  -1*-7

=4+         +6n      +7

=4++6n+7

=4+6n+7

=11+6n

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I've put in a lot of extra steps to help you understand.

this how quick it will be when you get the hang of it.

4- (-6n - 7)=4+6n+7=11+6n

Actually if you have a negative outside a bracket it has the effect of changing all the signs inside the bracket so

-(x+2)=-x-2

-(3-y)=-3+y

-(-p-5)=p+5