How do you solve the following system: $-2x + 5y = 20, x + y = 4$ ?

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Answer 1 · 2018-03-30T09:44:10

Just arrange the equation. Get $x=0$ and $y=4$

$-2x + 5y = 20$
$2x +2y = 8$

(after expanding the second equation by 2).

Now combine these equations:

$5y + 2 y = 20+8$

$7y = 28$

$y=28/7$

$y=4$

Now put this value into the second equation:

$x+y=4$

$x=4-y$

$x=4-4=0$

How do you solve the following system: -2x + 5y = 20, x + y = 4-2x + 5y = 20, x + y = 4?