Question

determine o valor de (x e y) sistema linear
-2x+8y=52
-5x+9y=42

Answer 1

I)-2x +8y = 52

II)-5x +9y = 42

Multiplicando a equação I por -5 e a II por 2, obtemos:

I)10x -40y = -260

II)-10x +18y = 84

Somando as duas, os fatores de x somam zero:

-22y = -176

y = -176/-22

y= 8.

Agora, substituindo y em uma das equações:

I)-2x +8.8 = 52

-2x + 64 =52

-2x = 52 - 64

-2x = -12

x = -12/-2

x =´6.

Answer 2

Oi...

- 2x + 8y = 52

- 5x + 9y = 42

Método da Substituição.

$9y=5x+42\\\\y=5x/9+14/3\\\\-2x+8(5x/9+14/3)=52\\\\-2x+40x/9+112/3=52\\\\-18x+40x+336=468\\\\22x+336=468\\\\22x=468-336\\\\22x=132\\\\x=132/22\\\\x=6\\\\\\y=5x/9+14/3\\\\y=(5/9).(6)+14/3\\\\y=5/3.2+14/3\\\\y=10/3+14/3\\\\y=10+14/3\\\\y=24/3\\\\y=8\\\\\\S= {x=6~e~y=8}$

Espero ter ajudado.