Respuesta :

amiamcwhite

Answer:

z= -3.1111111111

Step-by-step explanation:

-7*3=-21

-7*51= -357

-7*-39= 273

-21z+(-357)+273

simplify

-21z-84

-21z/-21 (canceled)

84/-21= 3.1111111111

Hope this helps.