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2010-03-07T15:41:46+01:00
A)
2x - 3y = 7 / * 5
3x - 5y = 11 / * (-3)

10x - 15y = 35
-9x + 15y = -33
x=2

x =2
10*2 - 15y =35

x=2
-15y=35-20

x=2
-15y=15 / : (-15)

x=2
y= -1

b)
5p - 2r = 21 / * 5
3p + 5r = -6 / * 2

25p -10r = 105
6p +10r = -12
31p = 93 /: 31

p = 3

p=3
6*3 +10r = -12

p=3
10r= -12 - 18

p=3
10r= -30 / : 10

p=3
r= -3

c)
2x - 3y = 10 / * 5
5x + 5y = 0 / * 3

10x - 15y= 50
15x + 15y= 0
25x=50 / :25

x=2

x=2
5*2+5y=0

x=2
5y= - 10 / :5

x=2
y= -2



  • Użytkownik Zadane
2010-03-07T15:47:14+01:00
A {2x-3y=7 -> 2x=3y-7 -> x=1,5y-3,5
3x-5y=11

3(1,5y-3,5)-5y=11
4,5y - 10,5 -5y =11
-0,5y=21,5
y=-43
x= 61



b)
5p - 2r = 21 / * 5
3p + 5r = -6 / * 2

25p-10r=105
6p+10r=-12

31p=93
p=3
75-10r=105
10r=30
r=3
c {2x-5y=10 ->5y=10-2x
5x+5y=0
5x +10-2x=0
3x=-10
x=-10/3
5y=10+6 2/3
5y=50/3
y=10/3

d {5v1+4v2=4
7v1+5v2=6

e {4x+5y=12,3/x3
3x-2y=-4/x -4

12x+15y=36,9
-12x+8y=16
23y=52,9
y=2,3
x=0,2
f {3x-0,2y=35 -> y=15x-175
2,5x-5y=5

2,5x-75x+875=5
-72,5x=-870
x=12
y=5