How do you solve the system $2 x + y = 0$ $2x + y = 0$ and $3 x - y = - 10$ $3x - y = - 10$ ?

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Answer 1 · 2015-05-16T17:16:35

One easy way to think this problem is by isolating one variable in one equation and substitute the value you find in the second equation, as follows:

For example, let's isolate $y$ $y$ in the first equation:

$y = - 2 x$ $y=-2x$

Now, let's just substitute this value we found in the second equation:

$3 x - (- 2 x) = - 10$ $3x-(-2x)=-10$
$5 x = - 10$ $5x=-10$
$x = (- \frac{10}{5}) = - 2$ $x=(-10/5)=-2$

Now, we know $x = - 2$ $x=-2$ and we can complete the value of $y$ $y$ , because we already know that $y = - 2 x$ $y=-2x$

Then, $y = - 2 (- 2)$ $y=-2(-2)$ .
$y = 4$ $y=4$ .

How do you solve the system 2x+y=02x + y = 0 and 3x−y=−103x - y = - 10?