How do you solve $2x + y = 5$ and $x + y = 4$ ?

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Answer 1 · 2018-03-29T07:37:40

$color(blue)(x=1)$ and $color(blue)(y=3)$

$2x+y=5\ \ \ \ [1]$

$x+y=4\ \ \ \ \ \ [2]$

Rearrange $[2]$ so y is in terms of $x$ :

$y=4-x \ \ [3]$

Substitute $[3]$ into $[1]$ :

$2x+(4-x)=5$

$2x+4-x=5$

$x=5-4=1$

Substitute this result into $[2]$ :

$1+y=4$

$y=4-1=3$

Result:

$color(blue)(x=1)$ and $color(blue)(y=3)$

How do you solve 2x + y = 52x + y = 5 and x + y = 4 x + y = 4?