What is the value of the x variable in the solution to the following system of equations?
7x - 2y = 21
4x + y = 57

21

-21

9

-9

Question

What is the value of the x variable in the solution to the following system of equations?
7x - 2y = 21
4x + y = 57 

 21 

 -21 

 9 

 -9

anonymous · Answer

Just tell me how to do it, don't give me the answer...please and thank you.

marissalovescats · Answer

Since you are trying to find the x value, you want to look at what you can do to the equations to cancel out the ys.

marissalovescats · Answer

So what can you do to the whole 2nd equation to cancel out the ys?

anonymous · Answer

subtract Y from both sides?

marissalovescats · Answer

No. It's called elimination. What can you multiply the 2nd equation by to cancel out the ys? -2y + what will have you no ys at all?

anonymous · Answer

Y? I'm not sure, I am so lost lol. It's been a while

marissalovescats · Answer

Okay we have to find the x. So you agree that means we have to eliminate the ys right?

anonymous · Answer

yes..

marissalovescats · Answer

Okay so what makes -2y zero? What can we add to -2y to make it zero and cancel out the ys?

anonymous · Answer

+2y

marissalovescats · Answer

Okay so that means what do we multiply the 2nd equation by to get that y to 2y?

anonymous · Answer

-1, or -y

marissalovescats · Answer

You said we wanted 2y. y times what gives us 2y?

anonymous · Answer

2

marissalovescats · Answer

Good

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Now what is new new 2nd equation after we times it by 2?