а) Умножаем обе части уравнения \( 2x = -5 \) на \( -3 \):
\[ 2x \cdot (-3) = -5 \cdot (-3) \]
\[ -6x = 15 \]
б) Умножаем обе части уравнения \( 2x = -5 \) на \frac{1}{2}:
\[ 2x \cdot \frac{1}{2} = -5 \cdot \frac{1}{2} \]
\[ x = -\frac{5}{2} = -2.5 \]
а) \( -5x = 60 \):
\[ -5x : (-5) = 60 : (-5) \]
\[ x = -12 \]
б) \(\frac{2}{3}x = -18 \):
\[ x = -18 : \frac{2}{3} \]
\[ x = -18 \cdot \frac{3}{2} \]
\[ x = -27 \]
а) \( 2 - x = 3x - 4 + 2y \);
\[ 2 - x - 3x + 4 - 2y = 0 \]
\[ 6 - 4x - 2y = 0 \]
б) \( 17 = 7 - 5x - 0,4y \);
\[ 17 - 7 + 5x + 0,4y = 0 \]
\[ 10 + 5x + 0,4y = 0 \]
а) \( 13x - 2 = 15x - 16 \);
\[ 13x - 15x = -16 + 2 \]
\[ -2x = -14 \]
\[ x = -14 : (-2) \]
\[ x = 7 \]
б) \( 24 + 6x = 15 + 3x \);
\[ 6x - 3x = 15 - 24 \]
\[ 3x = -9 \]
\[ x = -9 : 3 \]
\[ x = -3 \]