Respuesta :

Answer:

d =14

Step-by-step explanation:

[tex]1\frac{1}{2} d -9 =12[/tex]

[tex]\frac{3}{2} d = 12+ 9[/tex]

[tex]\frac{3}{2} d =21[/tex]

[tex]d = 21 : \frac{3}{2}[/tex]

[tex]d = 14[/tex]