найдите корень уравнения 1)8у-3(2у-3)=7у-2(5у+8) 2)5(2у-9)+6у=4(3у-2)-21 Решите уравнение 1)5(3-2у)-4(9-у)=3(у+5) 2)14(2х-3)-5(х+4)=2(3х+5)+5х 3)9(3х-7)+3(8х-11)=3(9х+8) 4)6(7х-11)-13(х-6)=14(2х+1)

Решим уравнения:

1) 8у - 3(2у - 3) = 7у - 2(5у + 8);

8y - 6y + 9 = 7y - 10y - 16;

2y +9 = - 3y - 16;

2y + 3y = - 16 - 9;

5y = - 25;

y = - 5.

2) 5(2у - 9) + 6у = 4(3у - 2) - 21;

10y - 45 + 6y = 12y - 8 - 21;

16y - 45 = 12y - 29;

16y - 12y = - 29 + 45;

4y = 16;

y = 4.

3) 5(3 - 2у) - 4(9 - у) = 3(у + 5);

15 - 10y - 36 + 4y = 3y + 15;

- 21 - 6y = 3y + 15;

- 6y - 3y = 15 + 21;

- 9y = 36;

y = - 4.

4) 14(2х - 3) - 5(х + 4) = 2(3х + 5) + 5х;

28x - 42 - 5x - 20 = 6x + 10 + 5x;

23x - 62 = 11x + 10;

23x - 11x = 10 + 62;

12x = 72;

x = 6.

5) 9(3х - 7) + 3(8х - 11) = 3(9х + 8);

27x - 63 + 24x - 33 = 27x + 24;

51x - 96 = 27x + 24;

51x - 27x = 24 + 96;

24x = 120;

x = 5.

6) 6(7х - 11) - 13(х - 6) = 14(2х + 1);

42x - 66 - 13x + 78 = 28x + 14;

29x + 12 = 28x + 14;

29x - 28x = 14 - 12;

x = 2.

Cоставим уравнения:

1) 1,2 + 7 = 2х + 3;

8,2 = 2x + 3;

8,2 - 3 = 2x;

2x = 5,2;

x = 2,6.

2) 8,3 - 2,1х = 2(1,5х + 11,8);

8,3 - 2,1x = 3x + 23,6;

- 2,1x - 3x = 23,6 - 8,3;

- 5,1x = 15,3;

x = - 3.

3) 9(13 - 0,8х) + 6,7 = 7,1х - 5;

117 - 7,2x + 6,7 = 7,1x - 5;

123,7 - 7,2x = 7,1x - 5;

- 7,2x - 7,1x = - 5 - 123,7;

-14,3x = - 128,7;

x = 9.