Respuesta :

Answer:

10.5

Step-by-step explanation:

common denominator for 7z and 3z is 21z

4/7z = 12/21z

2/3z = 14/21z

12/21z + 14/21z = 13

26/21z = 13

cross-multiply to get:

26z = 273

z = 273/26

z = 10.5

Answer:

z = 10.5

Step-by-step explanation:

(4/7)z + (2/3)z = 13

multiply by 21 to eliminate the fractions

12z + 14z = 273

26z = 273

Divide both sides by 26

z = 10.5