Question

ayuda!! SISTEMA DE ECUACIONES 2X2POR METODO DE SUSTITUCION

1) 3x - 2y= 8
2) 4x + y = 7​

Answer 1

Explicación paso a paso:

$4x + y = 7 \\ y = 7 - 4x \\ 3x + 2y = 8 \\ 3x + 2(7 - 4x) = 8 \\ 3x + 14 - 8x = 8 \\ 14 - 5x = 8 \\ - 5x = 8 - 14 \\ - 5x = - 6 \\ 5x = 6 \\ x = \frac{6}{5}$

$y = 7 - 4x = 7 - 4 \times \frac{6}{5} = \\ = 7 - \frac{24}{5} = \frac{35}{5} - \frac{24}{5} = \frac{11}{5 } \\ y = \frac{11}{5}$

$3 \times \frac{6}{5} + 2 \times \frac{11}{5} = \frac{18}{5} + \frac{22}{5} = \frac{40}{5} = 8$

$4 \times \frac{6}{5} + \frac{11}{5} = \\ = \frac{24}{5} + \frac{11}{5} = \frac{35}{5} = 7$

espero te sirva