SOLUTION: Find the solution to the following system of linear equations: 3x + 4y = -8 and y = -5x - 7 Thank you

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Question 164973: Find the solution to the following system of linear equations:

3x + 4y = -8 and
y = -5x - 7
Thank you
Answer by jim_thompson5910(21667) About Me  (Show Source):
You can put this solution on YOUR website!
Start with the given system
3x%2B4y=-8
y=-5x-7



3x%2B4%28-5x-7%29=-8 Plug in y=-5x-7 into the first equation. In other words, replace each y with -5x-7. Notice we've eliminated the y variables. So we now have a simple equation with one unknown.


3x%2B-20x-28=-8 Distribute


-17x-28=-8 Combine like terms on the left side


-17x=-8%2B28Add 28 to both sides


-17x=20 Combine like terms on the right side


x=%2820%29%2F%28-17%29 Divide both sides by -17 to isolate x



x=-20%2F17 Reduce




Now that we know that x=-20%2F17, we can plug this into y=-5x-7 to find y


y=-5x-7 Move onto the second equation


y=-5%28-20%2F17%29-7 Plug in x=-20%2F17


y=100%2F17-7 Multiply.


y=-19%2F17 Combine like terms.


So our answer is x=-20%2F17 and y=-19%2F17 which forms the ordered pair