Explicação passo-a-passo:
[tex] \dfrac{2x}{12} = \dfrac{4}{2} [/tex]
[tex]2x \times 2 = 12 \times 4[/tex]
[tex]4x = 48[/tex]
[tex]x = \dfrac{48}{4} [/tex]
[tex] \dfrac{3x}{9} = \dfrac{9}{3} [/tex]
[tex]3x \times 3 = 9 \times 9[/tex]
[tex]9x = 81[/tex]
[tex]x = \dfrac{81}{9} [/tex]
[tex] \dfrac{3x}{7} = \dfrac{6}{2} [/tex]
[tex]3x \times 2 = 7 \times 6[/tex]
[tex]6x = 42[/tex]
[tex]x = \dfrac{42}{6} [/tex]
[tex] \dfrac{x}{2} = \dfrac{8}{2} [/tex]
[tex]2x = 2 \times 8[/tex]
[tex]2x = 16[/tex]
[tex]x = \dfrac{16}{2} [/tex]
[tex]\large\boxed{\begin{array}{l} \sf{a) \: \dfrac{2x}{12} = \dfrac{4}{2} } \\ \\ \sf{4x = 12 \times 4} \\ \\ \sf{4x = 48} \\ \\ \sf{x = \dfrac{48}{4} } \\ \\ \boxed{ \sf{x = 12}} < < \sf{resposta}\end{array}}[/tex]
[tex]\large\boxed{\begin{array}{l} \sf{b) \: \dfrac{3x}{9} = \dfrac{9}{3} } \\ \\ \sf{9x = 9 \times 9} \\ \\ \sf{9x = 81} \\ \\ \sf{x = \dfrac{81}{9} } \\ \\ \boxed{ \sf{x = 9}} < < \sf{resposta}\end{array}}[/tex]
[tex]\large\boxed{\begin{array}{l} \sf{c) \: \dfrac{3x}{7} = \dfrac{6}{2} } \\ \\ \sf{6x = 6 \times 7} \\ \\ \sf{6x = 42} \\ \\ \sf{x = \dfrac{42}{6} } \\ \\ \boxed{ \sf{x = 7}} < < \sf{resposta}\end{array}}[/tex]
[tex]\large\boxed{\begin{array}{l} \sf{d) \: \dfrac{x}{2} = \dfrac{8}{2} } \\ \\ \sf{2x = 8 \times 2} \\ \\ \sf{2x = 16} \\ \\ \sf{x = \dfrac{16}{2} } \\ \\ \boxed { \sf{x = 8}} < < \sf{resposta}\end{array}}[/tex]
