Решение:
- \( 5x + 3x - 7 = 9 \)
\( 8x = 9 + 7 \)
\( 8x = 16 \)
\( x = 2 \) - \( 3y - 5 + y = 11 \)
\( 4y = 11 + 5 \)
\( 4y = 16 \)
\( y = 4 \) - \( 48 = 11 - 9a - 2 \)
\( 48 = 9 - 9a \)
\( 9a = 9 - 48 \)
\( 9a = -39 \)
\( a = -\frac{39}{9} = -\frac{13}{3} \) - \( 13 - 5x - 11 = 6x \)
\( 2 = 6x + 5x \)
\( 2 = 11x \)
\( x = \frac{2}{11} \)
Ответ: 1) x = 2; 2) y = 4; 3) a = -\(\frac{13}{3}\); 4) x = \(\frac{2}{11}\).