How do you solve the following system: $3x – y = 28 , 2x+5y=-1$ ?

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Answer 1 · 2015-12-26T07:41:14

The solution for the system of equations is
$color(blue)(x=139/17, y=(-59)/17$

$3x-y=28$ , multiplying this equation by $5$
$15x-color(blue)(5y)=140$ ......equation $(1)$

$2x+color(blue)(5y)=-1$ .......equation $(2)$

Solving by elimination

Adding equations $1$ and $2$

$15x-cancelcolor(blue)(5y)=140$

$2x+cancelcolor(blue)(5y)=-1$

$17x=139$

$color(blue)(x=139/17$

Finding $y$ by substituting $x$ in equation $1$

$3x-y=28$

$3 xx color(blue)(139/17)-y=28$

$(417/17)-y=28$

$(417/17)-28=y$

$(417/17)-476/17=y$

$color(blue)(y=-59/17$

How do you solve the following system: 3x – y = 28 , 2x+5y=-1 3x – y = 28 , 2x+5y=-1 ?