Step-by-step explanation:
[tex] = (7z + 1) + ( - 4z - 5)[/tex]
[tex] = 7z + 1 - 4z - 5[/tex]
[tex] = 7z - 4z + 1 - 5[/tex]
= 3z - 4
hence 3z - 4 is the answer...
hope it helped !!!
