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  • Użytkownik Zadane
2009-09-27T17:55:10+02:00
A)
{x+2y=9
{y-1=3x

{x+2y=9 /*3
{-3x+y=1

{3x+6y=27
+{-3x+y=1
_________
7y=28/:7
y=4

x+2y=9
x+2*4=9
x=9-8
x=1

b)
{x-y=2
{½x-1=¼y

{x-y=2
{½x-¼y=1/*(-2)

{x-y=2
+{-x+½y=-2
___________
-½y=0
y=0

x-y=2
x-0=2
x=2

{x=2
{y=0

c)
{-x-y=2
{3(3x+y)=-20

{-x-y=2 /*3
{9x+3y=-20

{-3x-3y=6
+{9x+3y=-20
____________
6x=-14/:6
x=-2⅓

-x-y=2
-(-2⅓)-y=2
2⅓-2=y
y=⅓

{x=-2⅓
{y=⅓
2009-09-27T17:57:45+02:00
×+2γ=9
γ-1=3×

x=9-2y
y-1=3(9-2y)

x=9-2y
y-1=27-6y

x=9-2y
-1-27=-6y-y

x=9-2y
-28=-7y/:(-7)

x=9-2y
y=4

x=9-8
y=4

x=1
y=4