what is 5(n-8) + 6(7-2n)

Question

My teacher told me when a minus sign is in a parenthesis like this its not subtraction is a negative, im super confused, i cant find help in my text book or notes.. 

Answer 1

5(n-8)+6(7-2n) can be written as...

5[n+(-8)]+6[7+(-2n)]=5n+5(-8)+6(7)+6(-2n)

                                   5n+5(-8)+6(7)+6(-2n)=5n+(-40)+42+(-12n)

                                                                     =5n+(-12n)+(-40)+42

                                                                     =-7n+2

however, you really don't have to do this...

5(n-8)+6(7-2n)=5n-40+42-12n=-7n+2