Z-4/9z=4'9 помогите срочно я тупой

z-(4/9)z=4.5

4.5=45/10

z(1-4/9)=45/10

5/9z=45/10

z=45/10*9/5=81/10=8.1 

или

z-4/9z =4.5

(9z-4)/9z=4.5

9z-4=40,5z

z(9-40,5)=4

z=4/(9-40.5)=4/31.5=8/63