Question

What is -2-(9-10n) please help it could change my life. It would be very nice

Answer 1

distribution property
a(b+c) = ab*ac

now, why does this matter

cause
-(9-10n) is equivalent to -1*(9-10n)

applying distribution property
-1*(9-10n) = -1*9 +-1-10n= -9 +10n