Answer:
a = 19
Step-by-step explanation:
[tex] \frac{3a - 1}{8} = \frac{a + 9}{4} [/tex]
[tex]4(3a - 1) = 8(a + 9)[/tex]
[tex]12a - 4 = 8a + 72[/tex]
[tex]12a - 8a = 72 + 4[/tex]
[tex]4a = 76[/tex]
[tex]a = 76 \div 4[/tex]
[tex]a = 19[/tex]
