Question

Prosze o rozwiazanie tych ukladow rownan metoda przeciwnych wspolczynnikow. DAM NAJ! :)
a) 7x= 14 i 1/2 b) 9/2x-3y=48 c) x+4y=12 d) 0,2x+0,3y=0,4
7x=8y+29 i 1/2 3/2+5/2y=-19 x+1/8y= 15/8 0,6x+0,7y=0,8

UWAGA!!! np 1/2 to sa ulamki jedna druga :)

Answer 1

A)
7x=14i1/2   /:7
7x=8y+29i1/2

x=14i1/2:7
7x=8y+29i1/2

x=29/2*1/7
x=29/14
x=2i1/14
7*2i1/14=8y+29i1/2
7*29/14=8y+59/2
203/14=8y+59/2
-8y=59/2-203/14
-8y=413/14-203/14
-8y=210/14   /:(-8)
y=210/14:(-8)
y=210/14*(-1/8)
y=-210/112
y=-1i7/8
b)
9/2x-3y=48
3/2+5/2y=-19

9/2x-3y=48
5/2y=-19-3/2
5/2y=-20i1/2   /*2/5
y=-41/2*2/5
y=-41/5
y=-8i1/5
9/2x-3*(-41/5)=48
9/2x+123/5=48
9/2x=48-24i3/5
9/2x=23i2/5   /*2/9
x=117/5*2/9
x=234/45
x=5i1/5
c)
x+4y=12
x+1/8y=15/8   /*(-1)

x+4y=12
-x-1/8y=-1i7/8
--------------------
3i7/8y=10i1/8   
31/8y=81/8   /*8/31
y=81/8*8/31
y=81/31
y=2i19/31
x+4*81/31=12
x+324/31=12
x=12-10i14/31
x=1i17/31
d)
0,2x+0,3y=0,4   /*3
0,6x+0,7y=0,8   /*(-1)

0,6x+0,9y=1,2
-0,6x-0,7y=-0,8
----------------------------
0,2y=0,4   /:0,2
y=2
0,2x+0,3*2=0,4
0,2x+0,6=0,4
0,2x=0,4-0,6
0,2x=-0,2   /:0,2
x=-1