1) -0.8y * 7x = (-0.8 * 7) * xy = -5.6xy;
2) 4 - (5x + 9y - 7) = 4 - 5x - 9y + 7 = -5x - 9y + 11;
3) - 6(-a - 3b + 4c) = 6a + 18b - 24c.
1) -0.8y * 7x = (-0.8 * 7) * xy = -5.6xy;
2) 4 - (5x + 9y - 7) = 4 - 5x - 9y + 7 = -5x - 9y + 11;
3) - 6(-a - 3b + 4c) = 6a + 18b - 24c.