Question

решите системы уравнений способом подстановки
1427. 1) [2(x+y)-x+6 = 0, 3x-(x - y) = 0; 2) [3(x+2y)-y-27 = 0, 14(x + y) - 3x-23 = 0; 3) [5x-2 (y + 4) = 0, 16(2x+3)-y-41 = 0; 4) [2x+3(x+y)-11 = 0, 7(x+3y) - 6x + 59 = 0. ​

Answer 1

Пошаговое объяснение:

1427.

1)

{2(x+y)-x+6=0

{3x-(x-y)=0

{2x+2y-x+6=0

{3x-x+y=0

{x+2y+6=0

{2x+y=0

{x+2y= -6

{2x+y=0 y= -2x

x+2(-2x)= -6

x-4x= -6

-3x= -6

x= -6:(-3)

x= 2

y= -2•2

y= -4

(2; -4)

2.

{3(x+2y)-y-27=0

{14(x+y)-3x-23=0

{3x+6y-y-27=0

{14x+14y-3x-23=0

{3x+5y= 27

{11x+14y=23

{3x=27-5y x=9-5/3y

{11x+14y=23

11(9-5/3y)+14y=23

99-55/3y+14y=23

-13/3y=23-99

-13/3y= -76

y= -76:(-13/3)

y=228/13

x=9-5/3•228/13=9-1140/39=351/39-1140/39=

= -789/39 = -263/13

(-263/13;228/13)

3.

{5х-2(у+4)=0

{16(2х+3)-у-41=0

{5х-2у-8=0

{32х+48-у-41=0

{5х-2у=8

{32х-у+7=0

{5х-2у=8

{32х-у= -7 у= 32х+7

5х-2(32х+7)=8

5х-64х-14=8

-59х=8+14

-59х=22

х=22:(-59)

х= -22/59

у=32•(-22/59)+7= -704/59+7= -291/59

( -22/59; -291/59)

4.

{2х+3(х+у)-11=0

{7(х+3у)-6х+59=0

{2х+3х+3у-11=0

{7х+21у-6х+59=0

{5х+3у=11

{х+21у= -59 х= -59-21у

5(-59-21у)+3у=11

-295-105у+3у=11

-102у=11+295

-102у=306

у=306:(-102)

у= -3

х= -59-21•(-3)

х= -59+63

х=4

(4;-3)