Question

Resolva o sistema a seguir utilizando numeros reais:

C)
$2x + y = 13 \\ 4x + 3y = 32$
D)

$x + y = 6 \\ 2x - y = 9$
E)
$3x - y = 10 \\ x + y = 18$
F)
$x + y = 10 \\ x - 3y = - 2$

(Me Ajudem urgente)​

Answer 1

c)

$2x + y = 13 \times ( - 3) \\ 4x + 3y = 32 \\ \\ - 6x - 3y = - 39 \\ 4x + 3y = 32 \\ \\ - 2x = - 7 \\ x = \frac{7}{2} \\ \\ y = 13 - 2x \\ y = 13 - 2 \times \frac{7}{2} \\ y = 13 - 7 \\ y = 6$

S = {(7/2, 6)}

d)

$x + y = 6 \\ 2x - y = 9 \\ 3x = 15 \\ x = \frac{15}{3} \\ x = 5 \\ \\ y = 6 - x \\ y = 6 - 5 \\ y = 1$

S = {(5, 1)}

e)

$3x - y = 10 \\ x + y = 18 \\ 4x = 28 \\ x = \frac{28}{4} \\ x = 7 \\ \\ y = 18 - x \\ y = 18 - 7 \\ y = 11$

S ={(7, 11)}

f)

$x + y = 10 \\ x - 3y = - 2 \times ( - 1) \\ \\ x + y = 10 \\ - x + 3y = 2 \\ 4y = 12 \\ y = \frac{12}{4} \\ y = 3 \\ \\ x = 10 - y \\ x = 10 - 3 \\ x = 7$

S ={(7, 3)}