Question

x+1/2(x-y)=15 2/3(x+y)-1/2x=-7 oblicz x i y

Answer 1

x+1/2(x-y)=15

2/3(x+y)-1/2x=-7

 

x+1/2x-1/2y=15   |*2

2/3x+2/3y-1/2x=-7    |*6

 

2x+x-y=30

4x+4y-3x=-42

 

x-y=30

x+4y=-42

_________   odejmujesz stronami

-5y=72

y=-72/5=-14 2/5

 

x-y=30

x-(-14 2/5)=30

x+14 2/5=30

x=30-14 2/5

x=15 3/5