How do solve the following linear system?: $2x + 4 = -4y, 7x + 6y + 11 = 0$ ?

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Answer 1 · 2017-06-17T17:16:22

$(-5/4,-3/8)$

First, solve one of the equations for $x$ . It doesn't matter which one.

$2x+4 = -4y$

$2x=-4-4y$

$x=-2-2y$

Next, plug this equation for $x$ into the other equation

$7color(red)(x)+6y+11=0$

$7(color(red)(-2-2y))+6y+11=0$

$-14-14y+6y+11=0$

$-14-8y+11=0$

$-3-8y=0$

$-8y=3$

$y=-3/8$

Finally, plug this solution for $y$ into the equation for $x$

$x=-2-2y$

$x=-2-2(-3/8)$

$x=-2+6/8$

$x=-16/8+6/8=-10/8=-5/4$

How do solve the following linear system?: 2x + 4 = -4y, 7x + 6y + 11 = 0 2x + 4 = -4y, 7x + 6y + 11 = 0 ?