[tex]\underset{\leftarrow \qquad \text{\LARGE 16x}\qquad \to }{\stackrel{12x + 4}{G\rule[0.35em]{10em}{0.25pt}} F\stackrel{16}{\rule[0.35em]{16em}{0.25pt}M}} \\\\\\ \stackrel{GF}{12x+4} ~~ + ~~ \stackrel{FM}{16} ~~ = ~~ \stackrel{GM }{16x}\qquad \implies 12x+20=16x \\\\\\ 20=4x\implies \cfrac{20}{4}=x\implies 5=x[/tex]
