Ответ:

[tex] - \frac{3}{7} (2.1x + 4 \frac{2}{3} y) + 2.2( - \frac{3}{11}x - \frac{5}{22} y) = - \frac{3}{7} (2.1x + \frac{14}{3} y) + \frac{22}{10} ( - \frac{3}{11} x - \frac{5}{22} y) = - \frac{9}{10} x - 2y - \frac{6}{10} x - \frac{1}{2} y = \frac{ - 9x - 20y - 6x - 10y}{10} = \frac{ - 15x - 30y}{10} [/tex]

При х=-1 1/3 ; у=1,2 будет

[tex] \frac{ - 15 \times - 1\frac{1}{3} - 30 \times 1.2 }{10} = \frac{ - 15 \times ( - \frac{4}{3}) - 36 }{10} = \frac{20 - 36}{10} = - \frac{16 }{10} = - 1.6[/tex]

Ответ: 1,6

Ответ:

-1

Пошаговое объяснение:

-3/7(2,1х + 4. 2/3у) + 2,2(-3/11х - 5/22у) =

-3/7(21/10х + 14/3у) + 22/10(-3/11х - 5/22у) =

-63/70х - 42/21у - 66/110х - 110/220у =

-9/10х - 2у - 3/5х - 1/2у =

(-9/10х - 3/5х) + (-2у - 1/2у) =

(-9/10х - 6/10х) + (-2. 1/2у) =

-15/10х - 2. 1/2у = -3/2х - 2. 1/2у =

-1. 1/2х - 2. 1/2у

х = -1. 1/3; у = 1,2

-1. 1/2х - 2. 1/2у = -1. 1/2 * (-1. 1/3) - 2. 1/2 * 1,2 =

-3/2 * (-4/3) - 5/2 * 12/10 = 12/6 - 60/20 = 2 - 3 = -1