[tex] \frac{2x}{5} = 6[/tex]

[tex] \frac{5}{2} \times \frac{2x}{5} = \frac{5}{2} \times 6[/tex]

[tex]x = 5 \times 3[/tex]

[tex]x = 15[/tex]

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[tex]3(23 - 4x) = 15[/tex]

[tex]23 - 4x = 5[/tex]

[tex] - 4x = 5 - 23[/tex]

[tex] - 4x = - 18[/tex]

[tex]x = \frac{9}{2} = 4.5[/tex]