Question

pliss ayuda ayuda no soy buena en matemáticas ​

Answer 1

Respuesta:

1) Ejercicio:

$\left \{ {{3x+8y=-6} \atop {6x-4y=7}} \right.$

$(-2)(3x+8y=-6)\\-6x-16y=12\\\\-6x-16y=12\\+6x-4y=7\\---------\\-20y=19\\y=-\frac{19}{20} \\\\6x-4(-\frac{19}{20})=7\\ 6x+\frac{19}{5}=7\\ 6x=7-\frac{19}{5}\\x= \frac{\frac{16}{5}}{6} \\x=\frac{16}{30}= \frac{8}{15}$

2) Ejercicio:

$\left \{ {{5x+9y=6} \atop {-10x+4y=2}} \right. \\\\2(5x+9y=6)\\10x+18y=12\\\\+10x+18y=12\\-10x+4y=2\\---------\\22y=14\\y=\frac{14}{22}=\frac{7}{11} \\\\5x+9(\frac{7}{11})=6\\5x+\frac{63}{11} =6\\5x=6-\frac{63}{11} \\x=\frac{\frac{3}{11} }{5} \\\\x=\frac{3}{55}$

3) Ejercicio:

$\left \{ {{-4x-2y=-3} \atop {8x-4y=3}} \right. \\\\2(-4x-2y=-3)\\-8x-4y=-6\\\\-8x-4y=-6\\+8x-4y=3\\---------\\-8y=-3\\y=\frac{3}{8} \\\\8x-4(\frac{3}{8})=3 \\8x-\frac{3}{2} =3\\8x=3+\frac{3}{2}\\\\x=\frac{\frac{9}{2} }{8} \\\\x=\frac{9}{16}$