How can x2 = 2x + 4 be set up as a system of equations?

y = x2 - 2x + 4
y = x2 + 2x + 4
y = x2
y = x2 + 2x + 4
y = x2 + 2x
y = x2 + 4

y = x2
y = 2x + 4
@ganeshie8 PLeaaase help me out?!

Question

How can x2 = 2x + 4 be set up as a system of equations?

 y = x2 - 2x + 4
y = x2 + 2x + 4
 y = x2
y = x2 + 2x + 4
 y = x2 + 2x
y = x2 + 4
 
y = x2
y = 2x + 4
@ganeshie8  PLeaaase help me out?!

directrix · Answer

x^2 = 2x + 4  looks like a step in solving a system of equations by substitution.

There are no y variables here so the substitution must or might have been for y.

y = x^2  and y = 2x + 4 could be the system of equations.

See what you think.  @iamabarbiegirl

directrix · Answer

There may be more than one correct answer option.

anonymous · Answer

okay so u think that its D? @Directrix

directrix · Answer

Option D is correct but also consider the others.

anonymous · Answer

oh okay! i get it thanks!! :D do you mind keeping an eye for more questions from me if i get stuck on some?

directrix · Answer

Looking at option A    y = x2 - 2x + 4,  y = x2 + 2x + 4
Substituting for y,

x^2 - 2x + 4 = x^2 + 2x + 4
The x^2 terms subtract off so option A is not correct.

directrix · Answer

That holds true for all the other options so I would go with option D.
-------
Yes, I'll keep an eye out for your problems. You can tag me if you like and I'll see if I know how to help.  @iamabarbiegirl

anonymous · Answer

alright thank you very much! :D I appreciate your help and time

directrix · Answer

You are welcome.

anonymous · Answer

please check this for me @Directrix 
Brad sold candy bars and cookies for a fundraiser at school. Candy bars sold for $3, and cookies sold for $5. He sold a total of 20 items and made $76. How many candy bars did Brad sell?

 12<----- MY ANSWER.
 14
 16
 18

directrix · Answer

I had to crank out the equations and solve.
I got 8 cookies and 12 bars.

anonymous · Answer

yayyy!! I got it right :D thanks @Directrix

directrix · Answer

Good to know.

anonymous · Answer

How can x + 4 = 3x + 12 be set up as a system of equations?

 

y = x + 1
y = -3x + 12
 

y = x + 2
y = -3x + 12
 

y = x + 4
                       <------- MY ANSWER 
y = 3x + 12
 

y = 4
y = -3x + 12
@Directrix

anonymous · Answer

stuck on this one @Directrix 
Which equation does the graph of the systems of equations solve?

quadratic graph opening down and quadratic graph opening up. They intersect at 0, 3 and 3, 0.

 x2 - 2x + 3 = 2x2 - 4x - 3
 x2 - 2x + 3 = 2x2 - 4x + 3
 -x2 + 2x + 3 = x2 - 4x + 3
 -x2 - 2x + 3 = x2 - 4x + 3

anonymous · Answer

@ganeshie8 @iambatman  please help me out guys.

directrix · Answer

On this problem, I agree with your answer. @iamabarbiegirl

How can x + 4 = 3x + 12 be set up as a system of equations?