Question

How Can I find ef? Do I multiply add or diving

Answer 1

$\bf \stackrel{eg}{5x+8}-\stackrel{fg}{3x}=\stackrel{ef}{6x-4}\implies2x+8=6x-4\implies 12=4x \\\\\\ \cfrac{12}{4}=x\implies 3=x\qquad \qquad \stackrel{ef}{6(3)-4}$


and surely you know how much that is.