Can someone help me with this please

Answer:
[tex]-2x-11z[/tex]
Step-by-step explanation:
You have to remember that,
[tex](-)*(-) = (+)\\(+)*(+)=(+)\\(-)*(+) = (-)[/tex]
lets solve now
[tex]-(7x+4z)-3x+(8x-7z)\\-7x-4z-3x+8x-7z\\-7x-3x+8x-4z-7z\\-10x+8x-11z\\-2x-11z[/tex]
hope this helps you
please let me know if you have any other questions :-)