[tex]5(x - 3) - 2(x - 7) = 7 - 7(2x + 6)[/tex]
[tex]5x - 15 - 2x + 14 = 7 - 14x - 42[/tex]
[tex]5x - 2x + 14x =7 - 42 + 15 - 14[/tex]
[tex]17x = - 34 \: | \div 17[/tex]
[tex]x = - 2 \: \in \: \mathbb{R}[/tex]
[tex]5(8x - 1) - 7(4x + 1) = 9 - 8(7 - 4x)[/tex]
[tex]40x - 5 - 28x - 7 = 9 - 56 + 32x[/tex]
[tex]40x - 28x - 32x = 9 - 56 + 5 + 7[/tex]
[tex] - 20x = - 35 \: | \div ( - 5)[/tex]
[tex]4x = 7[/tex]
[tex]x = \frac{7}{4} \: \in \: \mathbb{R}[/tex]
