Question

Resolva os sistemas de equações abaixo:
1){5X-8Y=-9
Y=6-x

2)3X+Y=-15
2Y=3X

3)4X-3Y=-2
-2X+4Y=1

Answer 1

1)5X-8(6-X)=-9                 Y=6-X

5X-48+8X=-9                    Y=3

13X=-9+48                           

13X=39                               X=3; Y=3

X=39/13

X=3

2)3X+Y=-15  (-2)

  -6X-2Y=-15                                          substituindo

  -3X+2Y=0                                            3x+y=-15   

Soma as esquações:                             3.(-10/3)+y=-15

-9x=30                                                   -30/3+y=-15

x=-30/9                                                  -10+y=-15

x=-10/3                                                  y=-15+10                   x=-10/3; y=-5

                                                              y=-5