Use graphing to find the solutions to the system of equations.
x^2 - y = 4
2x + y = -1

Will give fan and medal. Thank you in advance!!

Question

Use graphing to find the solutions to the system of equations.
x^2 - y = 4
2x + y = -1

Will give fan and medal. Thank you in advance!!

ray1998 · Answer

Hey @Alphabet_Sam , can you show me how to start this?

campbell_st · Answer

what graphing tools do you have..?

anonymous · Answer

Sure. Do you understand how to graph either, or do you need help with both?

ray1998 · Answer

Both please :)

campbell_st · Answer

just graph the 2 curves here then read off the point(s) of intersection https://www.desmos.com/calculator

anonymous · Answer

Are you allowed to use a graphing calculator?

ray1998 · Answer

Graphing paper and a pencil is what they normally have you use @campbell_st

ray1998 · Answer

Oh! Yes. Although, I don't have one with me

campbell_st · Answer

ok...so is this algebra or calculus..?

ray1998 · Answer

Algebra 2 @campbell_st

anonymous · Answer

What @campbell_st linked is a graphing calculator. You can just plug the two formulas in there, and then the solution is where the two graphs touch.

campbell_st · Answer

ok... so you need to solve the quadratic equation to find where it cuts the x-axis

I have rewritten the equation.

Can you solve

$$y = x^2 - 4$$

by setting y = 0

ray1998 · Answer

Okay :) thank you. @Alphabet_Sam

ray1998 · Answer

I think so, yes. @campbell_st

campbell_st · Answer

ok... so you need to solve 

$$0 = x^2 - 4$$

it can be factored

anonymous · Answer

Before you do that, the question asks you to solve by graphing. That's solving algebraically. It will produce the same answer, but if you are graded on your method it would be wrong.

campbell_st · Answer

to graph the curve you need to find some key information.... such as zeros or intercepts...

anonymous · Answer

Oh, you're right you can do it that way.

ray1998 · Answer

Is this the correct answer?

ray1998 · Answer

Where the points intersect from the formulas

ray1998 · Answer

Okay. Thank you guys @Alphabet_Sam and @campbell_st :) you guys are great.

campbell_st · Answer

is that a guess or you worked it out..?

ray1998 · Answer

I used the graphing calculator link that you posted.

triciaal · Answer

looks right

campbell_st · Answer

lol.... ok.... so much for the pencil and paper idea.... 


and its correct

ray1998 · Answer

Lol normally they have you do that or work on a calculator :) so either way. Thank you so much!