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

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

$0.5x + 0.15 = 0 \ 0.5x = - 0.15 \ x = - 0.3$
$7x - 11 = x - 6 \ 7x - x = 11 - 6 \ 6x = 5 \ x = frac{5}{6}$
$13 - 5x = 8 - 2x \ - 5x + 2x = 8 - 13 \ - 3x = - 5 \ x = frac{5}{3} = 1 frac{2}{3}$
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:
$8 - 0.8x = 0 \ 0.8x = 8 \ x = 10$