Multiply 3 by 4.
24.6+(4)3a=9.54.
24.6+12a=9.54.
Add 24.6 to 9.54.
12a=34.14.
Divide both sides by 12.
12a/12 = 34.14/12
A=2.845.
If you need the nearest whole number, it will be 3.
If you need it rounded to tenths, it will be 2.8
I hope this helps. Best of luck!