How do you solve the simultaneous equations $x + 2 y = 4$ $x+2y=4$ and $3 x - 4 y = 7$ $3x-4y=7$ ?

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How do you solve the simultaneous equations $x + 2 y = 4$ $x+2y=4$ and $3 x - 4 y = 7$ $3x-4y=7$ ?

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Answer 1 · 2015-08-09T07:09:16

$x = 3$ $x = 3$
$y = \frac{1}{2}$ $y = 1/2$

Explanation:

$x + 2 y = 4$ $x + 2y = 4$
$3 x - 4 y = 7$ $3x - 4y = 7$

Solve the first equation for $x$ $x$
$x = 4 - 2 y$ $x = 4 - 2y$

Substitute the value of $x$ $x$ into the second equation.
$3 (4 - 2 y) - 4 y = 7$ $3(4 - 2y) - 4y = 7$

Now there is only one variable present, so we can solve for $y$ $y$ .
$12 - 6 y - 4 y = 7$ $12 - 6y - 4y = 7$
$- 10 y = 7 - 12$ $- 10y = 7 - 12$
$y = (- \frac{5}{- 10})$ $y = (-5/-10)$
$y = \frac{1}{2}$ $y = 1/2$

Finally, substitute the value of $y$ $y$ into the first equation again
$x + 2 \cdot \frac{1}{2} = 4$ $x + 2 * 1/2 = 4$
$x + 1 = 4$ $x + 1 = 4$
$x = 4 - 1 = 3$ $x = 4 - 1 = 3$ #

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How do you solve the simultaneous equations $x + 2 y = 4$ $x+2y=4$ and $3 x - 4 y = 7$ $3x-4y=7$ ?

1 Answer

Explanation:

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How do you solve the simultaneous equations x+2y=4x+2y=4 and 3x−4y=73x-4y=7?

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How do you solve the simultaneous equations $x + 2 y = 4$ $x+2y=4$ and $3 x - 4 y = 7$ $3x-4y=7$ ?