Respuesta :

1: Add 9z to both sides.

−10z+9z=−9z+3+9z

−z=3

2: Divide both sides by -1.

−z/−1 = 3/−1

z=−3


-3 since your would do +9 with -10z which equals -1 which also equals -z=3 then you divide 3/-1 is -3