Question

1.
{1/2x + 2y =10
{x +4y = 20
2.
{1/2x -2y =10
{x +4y = 20

Answer 1

2.

{1/2x -2y =10
{x +4y = 20  / :2

 

{1/2x -2y =10
{1/2x +2y = 10  dodajemy stronami oba równania

______________________

x = 20

 

i z drugiego x+4y = 20 

20+4y = 20

4y = 0

y = 0

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{x = 20

{y = 0