Answer:
a = b/8
Step-by-step explanation:
The question is given as:
[tex]9a = \frac{(12a+3b)}{4}\\[/tex]
Multiplying both sides of above equation by '4',
[tex]4*9a = \frac{12a+3b}{4} *4\\36a = 12a+3b\\36a-12a = 3b\\24a = 3b\\[/tex]
Dividing both sides of above equation by '3',
[tex]\frac{24}{3} = b\\8a = b\\a = \frac{b}{8}[/tex]