120. Решите уравнения: a) 5x+13=2x-5; б) 10x-14=2x+18; в) -3x-17=1-9x; г) -4x+23=-4-13x.

Решение:

1. \( 5x + 13 = 2x - 5 \)

\( 5x - 2x = -5 - 13 \)
\( 3x = -18 \)
\( x = -6 \)
2. \( 10x - 14 = 2x + 18 \)

\( 10x - 2x = 18 + 14 \)
\( 8x = 32 \)
\( x = 4 \)
3. \( -3x - 17 = 1 - 9x \)

\( -3x + 9x = 1 + 17 \)
\( 6x = 18 \)
\( x = 3 \)
4. \( -4x + 23 = -4 - 13x \)

\( -4x + 13x = -4 - 23 \)
\( 9x = -27 \)
\( x = -3 \)

Ответ: a) \( x = -6 \); б) \( x = 4 \); в) \( x = 3 \); г) \( x = -3 \).