contestada

What is the result of adding these two equations?
\begin{aligned} -2x+7y &= -5 \\\\ -2x-4y &= 6 \end{aligned}
−2x+7y
−2x−4y
​

=−5
=6
​

=4
​

Respuesta :

guskarose

{-2x + 7y = -5

{-2x - 4y = 6              | · (-1)

{-2x + 7y = -5

{2x + 4y = -6               (+)

----------------------------------

-2x + 2x + 7y + 4y = -5 + (-6)

11y = -11          | : 11

y = -1

{y = -1

{2x + 4y = -6

{y = -1

{2x + 4 · (-1) = -6

{y = -1

{2x - 4 = -6       | + 4

{y = -1

{2x = -2              | : 2

{y = -1

{x = -1

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