Answer :

Add 4: -7n=28
Divide by -7: n=-4
AL2006
It's a simple linear equation in 'n'.  There's only one number that 'n' can be
that will make the equation a true statement.  That number is called the
'solution' to the equation.  Here's one way to find it:

You said that                        -7n - 4  =  24

Add  4  to each side:           -7n       =  28

Multiply each side by  -1 :    7n       =  -28

Divide each side by  7 :         n        =  -4

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