Question

Usando cramer resolva:
A) } 2 x - y = 3 / x + 4 y = 7

Answer 1

2 x - y = 3
x + 4 y = 7
________

__2__-1__
__1___4__

D=4.(2)-(-1).(1)

D=8-(-1)

D=8+1

D=9

_________

__3__-1__
__7__4___

Dx=3.(4)-(-1).(7)

Dx=12+7

Dx=19

________

___2_3__
___1__7_

Dy=7.2-(3).(1)

Dy=14-3

Dy=11

______

D=9

Dx=19

Dy=11

______

x=Dx/D

x=19/9

y=Dy/D

y=11/9

s=[(19/9;11/9)]

verificação:

2 x - y = 3
x + 4 y = 7

2.(19/9)-11/9=3

38/9-11/9=3

38-11/9=3

27/9=3

3=3

______

x+4y=7

19/9+4.(11/9)=7

19/9+44/9=7

19+44/9=7

63/9=7

7=7
_______________
espero ter ajudado!

boa noite!