Buenas tades,
1)
a)
<img src="https://tex.z-dn.net/?f=%20%5Cleft%20%5C%7B%20%7B%7B-7x-4y%3D-7%20%281%29%7D%20%5Catop%20%7B2x-y%3D2%282%29%7D%7D%20%5Cright.%20%20%5C%5C.%20%5C%5C%20%20Ec%20%281%29%3A%20%5C%5C%207x%3D7-4y%20%5C%5C%20x%3D1-%20%5Cfrac%7B4%7D%7B7%7D%20y%5C%5C.%20%5C%5C%20%20Ec%20%282%29%3A%20%5C%5C%202x%3D2%2By%20%5C%5C%20x%3D1%2B%20%5Cfrac%7B1%7D%7B2%7D%20y%20%20%5C%5C%20.%20%5C%5C%20x%3Dx%20%5C%5C%201-%20%5Cfrac%7B4%7D%7B7%7D%20y%3D1%2B%20%5Cfrac%7B1%7D%7B2%7D%20y%20%20%5C%5C%20y%3D0%20%20%5C%5C%20.%5C%5C%20y%5C%2C%5C%2C%20en%20%5C%2C%5C%2CEc%282%29%3A%20%5C%5C%202x%3D2%20%5C%5C%20x%3D1" />
Solución : x = 1 ; y = 0
b)
<img src="https://tex.z-dn.net/?f=%20%5Cleft%20%5C%7B%20%7B%7B2y%3D7-x%20%281%29%7D%20%5Catop%20%7B2y%3D-6x-8%282%29%7D%7D%20%5Cright.%20%5C%5C.%20%5C%5C%20%20Ec%281%29%3DEc%282%29%20%5C%5C%207-x%3D-6x-8%5C%5C%207x%3D15%20%5C%5C%205x%3D%20-15%5C%5Cx%3D-3%20%5C%5C%20.%5C%5C%20x%5C%2C%5C%2C%20en%20%5C%2C%5C%2CEc%281%29%3A%20%5C%5C%202y%3D7-%28-3%29%5C%5C%202y%3D10%5C%5Cy%3D5%20" />
Solución : x = - 3 ; y = 5
2)
a)
<img src="https://tex.z-dn.net/?f=%20%5Cleft%20%5C%7B%20%7B%7B2x%2B3y%3D1%20%281%29%7D%20%5Catop%20%7Bx%2By%3D-2%282%29%7D%7D%20%5Cright.%20%5C%5C.%20%5C%5CEc%281%29-2Ec%282%29%3A%20%5C%5C%20y%3D5%20%5C%5C%20.%20%5C%5C%20y%5C%2C%5C%2C%20en%20%5C%2C%5C%2CEc%282%29%3A%20%5C%5C%20x%2B5%3D-2%20%5C%5C%20x%3D-7" />
Solución : x = - 7 ; y = 5
b)
<img src="https://tex.z-dn.net/?f=%5Cleft%20%5C%7B%20%7B%7B-x%2B4y%3D3%20%281%29%7D%20%5Catop%20%7B3x%2B7y%3D10%282%29%7D%7D%20%5Cright.%20%5C%5C.%20%5C%5C3Ec%281%29%2BEc%282%29%3A%20%5C%5C%2019y%3D19%20%5C%5C%20%20y%3D1%5C%5C.%20%5C%5C%20%20y%5C%2C%5C%2C%20en%20%5C%2C%5C%2CEc%281%29%3A%20%5C%5C4%281%29%3D3%2Bx%20%5C%5C%20x%3D1" />
Solución : x = 1 ; y = 1.