Question

DOY CORONA En el sistema 10x + 5y = 2 y - 5x = 6 el valor de 3y - 15x es?

Answer 1

Explicación paso a paso:

$10x + 5y = 2y - 5x = 6 \\ \\ 10x + 5y = 6 \\ 10x = 6 - 5y \\ x = \frac{6 - 5y}{10} \\ 2y - 5x = 6 \\ - 5x = 6 - 2y \\ 5x = - 6 + 2y \\ x = \frac{ - 6 + 2y}{5} \\ x = x$

$\frac{6 - 5y}{10} = \frac{ - 6 + 2y}{5} \\ 30 - 25y = - 60 + 20y \\ 60 + 30 = 20y + 25y \\ 90 = 45y \\ y = \frac{90}{45} = 2 \\ y = 2$

$x = \frac{6 - 5y}{10} = \frac{6 - 5 \times 2}{10} = \frac{ 6 - 5 \times 2}{10} = \frac{6 - 10}{10} = \frac{ - 4}{10} = \frac{ - 2}{5} \\ x = \frac{ - 2}{5}$

$10 \times \frac{ - 2}{5} + 5 \times 2 = \frac{ - 20}{5} + 10 = - 4 + 10 = 6$

$2 \times 2 - 5 \times \frac{ - 2}{5} = 4 - \frac{ - 10}{5} = 4 - ( - 2) = 6$

$3y - 15x = 3 \times 2 - 15 \times \frac{ - 2}{5} = 6 - \frac{ - 30}{5} = 6 - ( - 6) = 12$

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