How do solve the following linear system?: $- 3 x + 7 y = - 16, x - 3 y = - 6$ $-3x + 7y= -16 , x - 3y = -6$ ?

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Answer 1 · 2018-05-16T13:51:56

$x = 45$ $x=45$ , $y = 17$ $y=17$

From the second equation, you have $x = 3 y - 6$ $x = 3y-6$ . Substitute this expression for $x$ $x$ in the first equation to get

$- 3 x + 7 y = - 16$ $-3x+7y=-16$

$\therefore -3(3y-6)+7y=-16$

$\therefore -9y+18+7y=-16$

$\therefore -2y=-34$

$\therefore y=17$

Once $y$ is known, we can derive $x$ :

$x = 3y-6 \implies x = 3*17-6 = 51-6 = 45$

How do solve the following linear system?: -3x + 7y= -16 , x - 3y = -6 −3x+7y=−16,x−3y=−6-3x + 7y= -16 , x - 3y = -6 ?