How do you solve $-2x + y = -1$ and $x + y = 5$ using substitution?

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Answer 1 · 2017-05-09T05:40:15

$x = 2, y = 3$

$-2x + y = -1$ ...................................(i)
$x + y = 5$ ................................................(ii)

From (i),
$y = 2x - 1$ ............................(iii)

Substituting y = 2x -1 in eq(ii),

$x + (2x - 1) = 5$

$rArr$ $x +2x - 1 = 5$

$rArr$ $3x = 6$

$rArr$ $x = 2$

Substituting x = 2 in eq (ii),
$2 + y = 5$

$rArr$ $y = 3$

How do you solve -2x + y = -1-2x + y = -1 and x + y = 5x + y = 5 using substitution?