Question

3x+7y= 11
3x-2y= -7
Qual o valor de x e y?
com calculo pfv
Obg

Answer 1

3 X + 7 Y = 11
3 X - 2 Y = -7 (multiplica por -1
-3 x + 2 y = 7
3 x +  7 y = 11
----------------- somar
0    + 9  y = 18
y = 18/9
y = 2
3 .x + 7 (2) = 11
 3 x  + 14  = 11
3 x = 11 - 14

3 x = -3
x = -3/3
x = -1