I need to perform the operation

(-5 -4x-1)+(-4-4x)

=-5 -4x-1-4-4x

=-9-8x-1

Full out like factors:

Factoring

The first term is,   its coefficient is  9 .

The middle term is,   its coefficient is  8 .

The last term, "the constant", is

Step-1 : Multiply the coefficient of the first term by the constant   9 • 1 = 9 

Step-2 : Find two factors of  9  whose sum equals the coefficient of the middle term, which is   8 .

what is the original number? you forgot to add it.

so, converting firstly the mixed fractions to improper fractions and then "adding".