Question

quanto e os valores de x e y no sistema:
3x+2y=12
-x+3y=7

Answer 1

$\left \{ {{3x + 2y = 12} \atop {-x + 3y = 7}} \right. \left \{ {{3x + 2y = 12} \atop {-3x + 9y = 21}} \right. \\\\ 11y = 33 \\ y = 3 \\\\ 3x + 2y = 12 \\ 3x + 2.3 = 12 \\ 3x = 12 - 6 \\ 3x = 6 \\ x = 2$

Answer 2

-x+3y = 7
3y = 7+x
y = (7+x)/3

3x+2.(7+x)/3 = 12
3x + (14 + 2x)/3 = 12 .(3)
9x + 3.(14+2x)/3 = 36
9x + 14 + 2x = 36
11x = 36 - 14
11x = 22
x = 22/11
x = 2

y = (7+x)/3
y = (7+2)/3
y = 9/3
y = 3