Question

Помогите плиз все примеры найти корень
(7x + 1) - (9x + 3) = 5
3,4 + 2y = 7(y - 2,3)
0,2(7-2y) = 2,3-0,3(y-6)

Answer 1

Ответ:

$x = - \frac{7}{2}$

$(7x + 1) - (9x + 3) = 5$

$7x + 1 - (9x + 3) = 5$

$7x + 1 - 9x - 3 = 5$

$- 2x + 1 - 3 = 5$

$- 2x - 2 = 5$

$- 2x = 5 + 2$

$- 2x = 7$

$x = - \frac{7}{2}$

$y = 3.9$

$3.4 + 2y = 7(y - 2.3)$

$3.4 + 2y = 7y - 16.1$

$3.4 + 2y - 7y = - 16.1$

$2y - 7y = - 16.1 - 3.4$

$- 5y = - 16.1 - 3.4$

$- 5y = - 19.5$

$y = 3.9$

$y = - 27$

$0.2(7 - 2y) = 2.3 - 0.3(y - 6)$

$1.4 - 0.4y = 2.3 - 0.3(y - 6)$

$1.4 - 0.4y = 2.3 - 0.3y + 1.8$

$1.4 - 0.4y = 4.1 - 0.3y$

$1.4 - 0.4 y + 0.3 = 4.1$

$- 0.4y + 0.3y = 4.1 - 1.4$

$- 0.1y = 4.1 - 1.4$

$- 0.1y = 2.7$

$y = - 27$