[tex]4.74 + 3(4a - 12) = 53.7 \times 0.2 \\ 4.74 + 3(4a - 12) = 10.74 \\ 3(4a - 12) = 10.74 - 4.74 \\ 3(4a - 12) = 6 \\ 4a - 12 = 6 \div 3 \\ 4a - 12 = 2 \\ 4a = 2 + 12 \\ 4a = 14 \\ a = 14 \div 4 \\ a = 3.5[/tex]
