SOLUTION: I have just started on equation substitutions. They are very confusing, and my entire 10th grade class is struggling. can you help me solve this substitution?
4x+y=-2 2x=-y
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4x+y=-2 2x=-y
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Question 120298: I have just started on equation substitutions. They are very confusing, and my entire 10th grade class is struggling. can you help me solve this substitution?
4x+y=-2 2x=-y Found 2 solutions by stanbon, jim_thompson5910:Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! 4x+y=-2 2x=-y
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Solve the "simpler" equation for "y":
y = -2x
Substitute that value of "y" in the other equation to solve for "x":
4x+(-2x)= 2
4x-2x = 2
2x = 2
x = 1
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Substitute that into y = -2x to solve for "y":
y = -2*1 = -2
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The solution for the system is (1,-2)
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Cheers,
Stan H.
Plug in into the first equation. In other words, replace each with . Notice we've eliminated the variables. So we now have a simple equation with one unknown.
Multiply
Combine like terms on the left side
Divide both sides by 2 to isolate x
Divide
Now that we know that , we can plug this into to find
Substitute for each
Simplify
So our answer is and which also looks like
Notice if we graph the two equations, we can see that their intersection is at (-1,2). So this verifies our answer.
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