Resposta:

a)

[tex]2x + 3( x - 5) = 4x + 9 \\ 2x + 3x - 15 = 4x + 9 \\ 5x - 4x = 9 + 15 \\ 1x = 24 \\ x = \frac{24}{1} \\ x = 24[/tex]

b)

[tex]2x - x + 1 = 5 - x + 3 \\ 2x - x + x = 5 + 3 - 1 \\ 2x = 7 \\ x = \frac{7}{2} [/tex]