Question

Calcule o valor de x e y
$\left \{ {{6x-5y=-1} \atop {4x+4y=3}} \right.$

Answer 1

$\left \{ {{6x-5y=-1} \atop {4x+4y=3}} \right. <=> \left \{ {{6x-5y=1} \atop {4y=3-4x}} \right. <=> \left \{ {{6x = 1 + 5y} \atop {y = \frac{3}{4} -x}} \right. <=> \\ -------------------- \\ \left \{ {{6x = 1 + 5( \frac{3}{4}-x) } \atop {y = \frac{3}{4}-x }} \right. <=> \left \{ {{6x = 1 + \frac{15}{4}-5x } \atop {y= \frac{3}{4}-x }} \right. <=> \left \{ {{x= \frac{19}{4} } \atop {y= \frac{3}{4} - \frac{19}{4} = \frac{-16}{4} }} \right.$

Answer 2

     6x - 5y = - 1(4)
     4x + 4y =  3(5)

     24x - 20y = - 4
     20x + 20y =  15
             44x = 11
     x =  11   ou x = 1
            44             4

 4x + 4y =  3 ==> 4y = 3 - 4.(1)
                                            4

4y = 3 - 1
4y = 2
  y =  2  ou y =  1
        4              2