How do you solve $2x + y = 7$ and $4x - y = 23$ ?

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Answer 1 · 2016-03-06T09:42:15

$x,y=5,-3$

$color(blue)(1) )color(blue)(2x+y=7$

$color(blue)(2))color(blue)(4x-y=23$

We can eliminate $y$ from the first equation by $-y$ in the second equation

Add both of the equations

$rarr(2x+y=7)+(4x-y=23)$

$rarr6x=30$

$color(green)(rArrx=30/6=5$

Now substitute the value of $x$ to the first equation

$rarr2(5)+y=7$

$rarr10+y=7$

$color(green)(rArry=7-10=-3$

How do you solve 2x + y = 72x + y = 7 and 4x - y = 23 4x - y = 23 ?