Question

Решите уравнения -x=- 1 3/5, 1/5=-5x, -6=1/6x, 3/7x=2/14, -0,81x=72,9, 2/3x=18, 3/4x=27, 2/7x=0, 3x+7=0, 13-100x=0,
0,5x+0,15=0, 7x-11=x-6, 8-0,8=0, 13-5x=8-2x

Answer 1

$- x = - 1 \frac{3}{5} \\ x = 1\frac{3}{5}$
$\frac{1}{5} = - 5x \\ x = \frac{1}{5} \div ( - 5) = - \frac{1}{25}$
$- 6 = \frac{1}{6} x \\ x = - 6 \times 6 = - 36$
$\frac{3}{7} x = \frac{2}{14} \\ 3x = \frac{7 \times 2}{14} = 1 \\ x = \frac{1}{3}$
$- 0.81x = 72.9 \\ x = \frac{72.9}{ - 0.81} = \frac{729}{10} \div ( - \frac{81}{100} ) = \frac{729}{10} \times ( - \frac{100}{81} ) = 9 \times ( - 10 ) = - 90$
$\frac{2}{3} x = 18 \\ x = 18 \div \frac{2}{3} = 18 \times \frac{3}{2} = 27$
$\frac{3}{4} x = 27 \\ x = 27 \div \frac{3}{4} = 27 \times \frac{4}{3} = 9 \times 4 = 36$
$\frac{2}{7} x = 0 \\ x = 0$
$3x + 7 = 0 \\ 3x = - 7 \\ x = - \frac{7}{3} = - 2 \frac{1}{3}$
$13 - 100x = 0 \\ 100x = 13 \\ x = \frac{13}{100} = 0.13$

$0.5x + 0.15 = 0 \\ 0.5x = - 0.15 \\ x = - 0.3$
$7x - 11 = x - 6 \\ 7x - x = 11 - 6 \\ 6x = 5 \\ x = \frac{5}{6}$
$13 - 5x = 8 - 2x \\ - 5x + 2x = 8 - 13 \\ - 3x = - 5 \\ x = \frac{5}{3} = 1 \frac{2}{3}$
8 - 0,8 = 0 (где х?)
если х возле 8:
$8x - 0.8 = 0 \\ 8x = 0.8 \\ x = 0.1$
если х возле -0,8:
$8 - 0.8x = 0 \\ 0.8x = 8 \\ x = 10$