How do you solve the following system?: $x - 3 y = 0, 3 x + y = 7$ $x - 3y = 0 , 3x + y = 7$

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How do you solve the following system?: $x - 3 y = 0, 3 x + y = 7$ $x - 3y = 0 , 3x + y = 7$

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Answer 1 · 2018-05-03T21:32:57

$x = \frac{21}{10}$ $x=21/10$ and $y = \frac{7}{10}$ $y=7/10$

Explanation:

$x - 3 y = 0$ $x-3y=0$
$3 x + y = 7$ $3x+y=7$

Let's solve for $x$ $x$ in the first equation so we can use substitution

$x = 3 y$ $x=3y$

Now plug that into the second equation

$3 (3 y) + y = 7$ $3(3y)+y=7$

$9 y + y = 7$ $9y+y=7$

$10 y = 7$ $10y=7$

$y = \frac{7}{10}$ $y=7/10$

Plug that back into the first equation:

$x = 3 (\frac{7}{10})$ $x=3(7/10)$

$x = \frac{21}{10}$ $x=21/10$

$. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$ $. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$

To check our work, let's substitute $\frac{21}{10}$ $21/10$ and $\frac{7}{10}$ $7/10$ for $x$ $x$ and $y$ $y$ and solve. If we get the same answer as the equation, we are correct

$3 x + y = 7$ $3x+y=7$

$3 (\frac{21}{10}) + (\frac{7}{10})$ $3(21/10)+(7/10)$ should equal $7$ $7$

$\frac{63}{10} + \frac{7}{10}$ $63/10+7/10$

$\frac{70}{10}$ $70/10$

$7$ $7$ equals $7$ $7$

We were right!

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How do you solve the following system?: $x - 3 y = 0, 3 x + y = 7$ $x - 3y = 0 , 3x + y = 7$

1 Answer

Explanation:

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Impact of this question

Science

Math

Humanities

... and beyond

How do you solve the following system?: x−3y=0,3x+y=7 x - 3y = 0 , 3x + y = 7

1 Answer

Explanation:

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Impact of this question

How do you solve the following system?: $x - 3 y = 0, 3 x + y = 7$ $x - 3y = 0 , 3x + y = 7$