Question

Solve the system of equations. 2y+7x=−5 5y−7x=12 ​

Answer 1

We can solve this by substitution method.

Look at the second equation. If we rearrange to find 7x, we can substitute in the value into the first equation.

$5y-7x=12$

$5y-7x-12=0$

$5y-12=7x$

Therefore, $7x=5y-12$

Now replace the 7x in the first equation with 5y - 12:

$2y+7x=-5$ (substitute in 7x = 5y - 12)

$2y+(5y-12)=-5$

$7y-12=-5$

$7y=7$

$y=1$

Now that we know y, we can find x by substituting in y = 1 into any equation we want. I will use the equation: 7x = 5y - 12

$7x=5y-12$ (substitute in y = 1)

$7x=5(1) -12$

$5x=5-12$

$7x=-7$

$x=-1$

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Answer:

$y=1\\x=-1$