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

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Answer 1 · 2017-03-27T16:07:24

See the entire solution process below:

Step 1) Because the second equation is already solved for $y$ , substitute $3x$ for $y$ in the first equation and solve for $x$ :

$-7x + 2y = 7$ becomes:

$-7x + 2(3x) = 7$

$-7x + 6x = 7$

$(-7 + 6)x = 7$

$-1x = 7$

$color(red)(-1) xx -1x = color(red)(-1) xx 7$

$1x = -7$

$x = -7$

Step 2) Substitute $-7$ for $x$ in the second problem and calculate $y$ :

$y = 3x$ becomes:

$y = 3 xx -7$

$y = -21$

The solution is: $x = -7$ and $y = -21$ or $(-7, -21)$

How do you solve the system of equations -7x + 2y = 7-7x + 2y = 7 and y = 3xy = 3x?