Ask your own question, for FREE!
Mathematics 13 Online
rebeccaxhawaii (rebeccaxhawaii):

can someone pls help me with some questions involving algebra 2 ? PPPPPPPPPPPPPPPLLLLLLLLLLLLLLLLLEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAASSSSSSSSSSSSSSSSSSSSSSEEEEEEEEEEEEEEEEEEEE

OpenStudy (timbo5lice):

what is it?

rebeccaxhawaii (rebeccaxhawaii):

okay so my equation is x^2-16 and it says to Identify the key features of your graph. and Explain how to find them algebraically.

OpenStudy (johnweldon1993):

Well, it would be an upwards facing parabola with a vertex *minimum point* at y = -16

OpenStudy (johnweldon1993):

I only know that because the equation of a parabola *or quadratic* is \(\large ax^2 + bx + c\) So now the key features you can find from this are the minimum point and the point(s) where the parabola crosses the 'x' axis

rebeccaxhawaii (rebeccaxhawaii):

so yes i understand that part of the vertex on -16 and facing upward but i dont understand like what they are asking for

OpenStudy (johnweldon1993):

Well basically they want to know how you can solve for those algebraically

rebeccaxhawaii (rebeccaxhawaii):

which means ?

OpenStudy (johnweldon1993):

So remember how I said the equation of a parabola is \(\large y = ax^2 + bx + c\) How do you find the vertex if you cannot see the graph? well you use the equation \[\large -\frac{b}{2a}\] And then how would you find where the parabola crosses the x-axis? You could factor it, or use the quadratic formula

rebeccaxhawaii (rebeccaxhawaii):

im sorry i am so lost dont i just tell them how i got my answer ? idk

OpenStudy (johnweldon1993):

Yeah that's it, dont overthink it :) They want to hear, okay what do you think the vertex is based on the graph? Then back that up by actually solving for it and they want to know when the graph crosses the 'x' axis...and then tell them how you would solve for that

rebeccaxhawaii (rebeccaxhawaii):

it passes x at -4 and 4 right ? and i say i got -16 vertex because f(x)=x^2-16 the last number is the vertex

OpenStudy (johnweldon1993):

The -4 and 4 are correct yes *and you solved that using what method?* And well the vertex is at the point (0,-16) *I remember losing points because of that one time >.< lol but yeah other than that you're good :) *****also, the last number is not ALWAYS the vertex :)

rebeccaxhawaii (rebeccaxhawaii):

i just graphed it on Desmos lol

rebeccaxhawaii (rebeccaxhawaii):

but ik im probably annoying you with stupid question but could you spare a little more time

OpenStudy (johnweldon1993):

...I dont think they'll take that as an answer ;) XD But no, say you used the quadratic formula to solve for that -4 and 4

rebeccaxhawaii (rebeccaxhawaii):

okok thank you

OpenStudy (johnweldon1993):

And no I never get annoyed... okay thats a lie..but you're good XD

rebeccaxhawaii (rebeccaxhawaii):

hold on let me write my answers down but i have another question so prepare yourself for frustration

OpenStudy (johnweldon1993):

....I might need a snack for this... XDD I'll be ready!!

rebeccaxhawaii (rebeccaxhawaii):

still alive ?

rebeccaxhawaii (rebeccaxhawaii):

if so this is my next question

rebeccaxhawaii (rebeccaxhawaii):

Using your graph from question 4, describe if the average rate of change is increasing or decreasing, from left to right. Justify your observations by comparing the slopes calculated between at least three different pairs of points.

OpenStudy (johnweldon1993):

...barely... haha yeah I'm here :P

rebeccaxhawaii (rebeccaxhawaii):

btw #4 is the question u just helped muah with

OpenStudy (johnweldon1993):

I mean we can really just LOOK at it and see...but I guess we need 3 points on the parabola for justification...tell me 3 points :)

rebeccaxhawaii (rebeccaxhawaii):

(-4,0) (4,0) (0,16)

rebeccaxhawaii (rebeccaxhawaii):

-16 *****

OpenStudy (johnweldon1993):

Haha cheater :P I wanted different ones...but oh well I didnt specify lol Oh so calculate the slopes between (-4,0) and (0,-16) and then the slope between (0,-16) and (4,0)

rebeccaxhawaii (rebeccaxhawaii):

okay okay

rebeccaxhawaii (rebeccaxhawaii):

u probably know this by just looking at it but us less fortunate beings have to write it down lol so the slopes are -4 and 4

OpenStudy (johnweldon1993):

XD I knew it from looking at the 2 points actually XD you get good at this after a while lol and hmm...i dont wanna confuse you...you are correct, but these points wont work Lets choose 2 other points like...(4,0) and (5,9) |dw:1446498829900:dw| We know the slope between (0,-16) and (4,0) is 4 right? what is the slope between these 2 new points?

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!