Question

rozwiaz uklady rownan metoda podstawiania

a{2x-y=10

{x+5y=-17

b {3m+n=9

{2m-5n+-11

c {4a-2=v

{3a+7b=1,5

Answer 1

a{2x-y=10

  {x+5y=-17

 

2x - y = 10

x = -17 - 5y

 

2(-17 - 5y) - y = 10

x = -17 - 5y

 

-34 - 10y - y = 10

x = -17 - 5y

 

-11y = 44 /:(-11)

x = -17 - 5y

 

y = -4

x = -17 + 20

 

y = -4

x = 3

 

b {3m+n=9

   {2m-5n =-11

 

n = 9 - 3m

2m - 5(9 - 3m)  = -11

 

n = 9 - 3m

2m - 45 + 15m = -11

 

n = 9 - 3m

17m = 34 / :(17)

 

n = 9 - 3m

m = 2

 

n = 9 - 6

m = 2

 

n = 3

m = 2

 

c {4a-2=b

  {3a+7b=1,5

 

4a - 2 = b

3a + 7(4a - 2) = 1,5

 

b = 4a - 2

3a + 28a - 14 = 1,5

 

b = 4a - 2

31a = 15,5 /:31

 

b = 4a - 2

a = 0,5

 

b = 4 * 0,5 - 2

a = 0,5

 

b = 0

a = 0,5