Respostas

2013-11-10T22:43:29-02:00
A) 4x+y=7
    2x-5y=9(-2)
    
    4x+y=7                               4x+y=7
   -4x+10y=-18                        4x+(-1)=7
    11y=-11                              4x-1=7
    y=-11/11                             4x=7+1
    y=-1                                     4x=8
                                                 x=8/4=2


b) 4x+3y=14*(5)
    5x-2y=29*(-4)
                                                       4x+3y=14
    20x+15y=70                               4x+3(-2)=14
   -20x+8y=-116                              4x-6=14
    23y=-46                                      4x=14+6
     y=-46/23                                    4x=20
     y=-2                                            x=20/4
                                                        x=5

Espero ter ajudado.
7 4 7
Atah. É porque tem hora que aparece tudo embaralhado.
atha
coloquei novas perguntas viu kk
ainda não.
vc vendo vc vai responder?