Question

Rozwiąż układy równań

a) 2 (x +y ) - (x - 1 )= x + y

x + y = 1

b) jedna druga ( x - 1) + y = - dwie całe i jedna druga

x - 7 = 1 - y

c) x - y x + y

---------- - -------- = - jedna druga

3 2

x + y =3

d) x ( x - 6 ) - x(y + x) = y(3 +- x)

2x +y = 0

Answer 1

a) 2x+2y-x-1=x+y

x=1-y

 

2x+2y-x-x-y=1

x=1-y

 

2y=1/:2

x=1-y

 

y=1/2

x=1-1/2

 

y=1/2

x=1/2

 

y=x

 

 

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

x-7=1-y

 

1/2x - 1/2+y=-2 1/2

x=8-y

 

1/2x+y= -2

x=8-y

 

1/2*(8-y)+y= -2

x=8-y

 

4- 1/2y +y=-2

x=8-y

 

1/2y=-6/*2

x=8-y

 

y=-12

x=8-(-12)

 

y=-12

x=20

 

c)    (x-y):3 - (x+y):2= -1/2

x=y-3

 

x/3 - y/3 - x/2+ y/2= -1/2

x=y-3

 

(y-3):3 -y/3- (y-3)/2= -1/2

x=y-3

 

y/3 - 1 - y/3 -y/2 - 1 1/3= -1/2

x=y-3

 

y/2=-1- 1 1/3 - 1/2

x=y-3

 

y/2=-2 1/3 - 1/2

x=y-3

 

y/2= -2 2/6 -3/6

x=y-3

 

y/2= -2 5/6 /*2

x=y-3

 

y= -3 2/3

x= -6 2/3