Answer :
[tex]z : 2 - 4z + 3(z - 3)= z\cdot \frac{1}{2} - 4z + 3 z - 9= -\frac{1}{2}z -9 \\ \\ z= 8 \\ \\-\frac{1}{2}z -9 =-\frac{1}{2} \cdot 8 -9 =-4-9=-13 \\ \\ Answer : \ B. \ \ -13[/tex]
[tex]3 \cdot 4 - 3 \cdot 7 = 3(x - 7) \\ \\ 12-21 =3x-21\\ \\3x =12-21+21\\ \\3x=12 \ \ /:3\\ \\ x=4 \\ \\ Answer : \ A. \ \ 4[/tex]
[tex]3 \cdot 4 - 3 \cdot 7 = 3(x - 7) \\ \\ 12-21 =3x-21\\ \\3x =12-21+21\\ \\3x=12 \ \ /:3\\ \\ x=4 \\ \\ Answer : \ A. \ \ 4[/tex]