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Mathematics 10 Online
OpenStudy (gnrfan):

Please help with math

OpenStudy (gnrfan):

1. To open these doors, you must match the number and type of solutions for the following two functions in standard form. f(x) = x2 + 6x – 16 g(x) = x2 +6x + 1 Match the following descriptions of the solutions to each of the functions above. Hint: they each have their own match. Two real irrationals solutions Two real rationals solutions 2. To pass by me, you must tell me how to convert standard form into the general, vertex form... I have a test on it next week.” Explain how to convert f(x) into the general, vertex form of the equation. Use complete sentences.

OpenStudy (gnrfan):

@Hero @iambatman can y'all help please. i need this done and it looks like chinese

OpenStudy (gnrfan):

@hartnn pls

OpenStudy (anonymous):

@gnrfan can you find the solutions for f(x)?

OpenStudy (anonymous):

first of all, just by looking at f(x) you should immediately know the number of solutions there is

OpenStudy (anonymous):

so can you tell how many solutions it has?

OpenStudy (gnrfan):

3 im guessing :/

OpenStudy (anonymous):

no

OpenStudy (anonymous):

ok so lets rewrite it properly, you need the ^ to show exponents ok?

OpenStudy (gnrfan):

yes

OpenStudy (anonymous):

so you have f(x) = x^2 + 6x – 16, correct?

OpenStudy (gnrfan):

on the bottom it shows a bunch of ? do you mean g(x) = x^2 +6x + 1?

OpenStudy (anonymous):

you may have to refresh the page, its a glitch, but yeah thats fine,

OpenStudy (anonymous):

ok so can you tell me the degree of the polynomial, x^2 + 6x + 1

OpenStudy (gnrfan):

hold while i solve it

OpenStudy (anonymous):

um ok

OpenStudy (anonymous):

you dont need to solve it to know the degree

OpenStudy (anonymous):

but you have to solve anyways, so might as well i guess, i was just trying to make a point

OpenStudy (gnrfan):

ph

OpenStudy (gnrfan):

well its 2

OpenStudy (anonymous):

ok the degree is two, so that means it will have 2 roots aka 2 solutions, whatever the degree of the polynomial is, it will have that many roots or solutions

OpenStudy (anonymous):

so if you have a polynomial of degree 5, it will have 5 solutions

OpenStudy (gnrfan):

k, got it

OpenStudy (anonymous):

ok so that doesnt help eliminate any answers since both answers have 2 solutions, so yeah now you need to find the roots of g(x) and the roots of f(x)

OpenStudy (anonymous):

and you need to determine which has rational solutions and which has irrational solutions

OpenStudy (anonymous):

so can you tell me the solutions for f(x) or g(x), ?

OpenStudy (gnrfan):

hold on

OpenStudy (anonymous):

k

OpenStudy (gnrfan):

what formula do I use to solve these?

OpenStudy (anonymous):

you can use the quadratic formula if you like, or you can just set f(x) = 0 and isolate x on one side (which is solving for x)

OpenStudy (anonymous):

i recommend you become familiar with both methods

OpenStudy (anonymous):

try the second method, first set f(x) = 0

OpenStudy (anonymous):

x^2 + 6x - 16 = 0

OpenStudy (anonymous):

now isolate x on one side of the equation

OpenStudy (gnrfan):

so f(x)=x^2+6x-16=0?

OpenStudy (anonymous):

yes thats valid, but get rid of the f(x)= part because we dont need it right now

OpenStudy (anonymous):

since we know what f(x) = you dont need to write it, its redundant

OpenStudy (gnrfan):

x=-8,2

OpenStudy (anonymous):

pefect, now is -8 a rational number? is 2 a rational number?

OpenStudy (gnrfan):

yes, i think. I kinda forgot how to tell

OpenStudy (anonymous):

ok a rational number can be represented as the ratio of two integers, put it another way, a fraction in which the numerator is an integer and the denominator is an integer

OpenStudy (anonymous):

you know what an integer is?

OpenStudy (gnrfan):

a whole number right

OpenStudy (anonymous):

yes its a whole number, more specifically its a whole number that can be positive or negative or 0

OpenStudy (anonymous):

ok so can we represent -8 as a ratio of two integers?

OpenStudy (gnrfan):

yes

OpenStudy (anonymous):

yes we can, we can have -8/1, -4/2, 4/-2 8/-1,

OpenStudy (gnrfan):

cool

OpenStudy (anonymous):

so -8 is a rational number

OpenStudy (gnrfan):

yes

OpenStudy (anonymous):

so tell me is sqrt(5) a rational number?

OpenStudy (gnrfan):

do you mean the sqrt of 5 or just sqrt of 5

OpenStudy (anonymous):

by the way i mean 16/-2 and -16/2 instead of 4/-2 and -4/2, sorry for the confusion lol

OpenStudy (gnrfan):

its rational

OpenStudy (anonymous):

square root of 5 is not rational, you cannot represent it as the ratio of two integers

OpenStudy (gnrfan):

oh, my bad

OpenStudy (anonymous):

so how about square root of 25 is that a rational number?

OpenStudy (gnrfan):

no, not rational

OpenStudy (anonymous):

actually square root of 25 is rational, because square root of 25 is either +5 or -5, and +5 can be represented as a ratio of two integers and -5 can be represented as a ratio of two integers

OpenStudy (gnrfan):

wow, well at least im learning this stuff instead of just being told im wrong by a teacher

OpenStudy (anonymous):

lol thats good, i hope you have better teachers in the future, either you or your parents need to talk to your teacher and the principal if necessary to discuss how you are not understanding and the teacher needs to explain it to you

OpenStudy (gnrfan):

yea, well whats next good sir?

OpenStudy (anonymous):

thats what the teacher is paid to do, so if they arent doing their job, they need to quit or be fired

OpenStudy (anonymous):

ok so now you can answer, the first question

OpenStudy (anonymous):

so what is the answer that matches f(x)

OpenStudy (anonymous):

Two real irrationals solutions or Two real rationals solutions

OpenStudy (anonymous):

remember the solutions were -8 and 2

OpenStudy (gnrfan):

two real rationals

OpenStudy (anonymous):

yep, so you know from the hint that that g(x) must be irrational, since the hint says each one has a match

OpenStudy (gnrfan):

yup

OpenStudy (anonymous):

if you work out the solutions for g(x) you will see they are -3 - 2sqrt(2), and 2sqr(2) - 3

OpenStudy (anonymous):

and since we know sqrt(2) is irrational, then -3 -2sqrt(2) must also be irrational, so that confirms our answer for g(x)

OpenStudy (gnrfan):

yea, can u help with the second part too?

OpenStudy (anonymous):

so do you need help with number 2 or you good on that?

OpenStudy (anonymous):

ok 1 sec, let me read it

OpenStudy (gnrfan):

lol

OpenStudy (anonymous):

lol

OpenStudy (anonymous):

ok so its asking you to write f(x) in vertex form , is that correct?

OpenStudy (gnrfan):

yup

OpenStudy (gnrfan):

but i gotta use complete sentences though. i hate that

OpenStudy (anonymous):

lol

OpenStudy (anonymous):

yeah its kinda annoying but not that hard

OpenStudy (anonymous):

so do you know the steps to convert standard form to vertex form?

OpenStudy (gnrfan):

give me something in standard form and i'll convert it and see if im right

OpenStudy (anonymous):

ok so lets use the problem as the example , so i have f(x) = x^2 + 6x - 16, that is currently in standard form, convert it to vertex form

OpenStudy (gnrfan):

y=(x+3)^2-25

OpenStudy (anonymous):

perfect, what method did you use to get that answer

OpenStudy (gnrfan):

i don't know. I just did the way i was taught

OpenStudy (anonymous):

you used completing the square right?

OpenStudy (gnrfan):

i think so

OpenStudy (anonymous):

ok well you dont have to call it completing the square if you dont want to, but yeah you understand how to do it, now can you tell me the first step you took.

OpenStudy (gnrfan):

first i put it equal to y, then i did the sqr on the right side, then i re-ordered the right side to match the parabola

OpenStudy (anonymous):

ok so if you were explaining it to someone trying to teach them, would that make any sense? what you just said, you need to write out sentences that would make sense to somebody just learning how to do it

OpenStudy (anonymous):

pretend you are teaching someone how to do it, explain in details each step so they can understand what you mean

OpenStudy (gnrfan):

k hold on

OpenStudy (gnrfan):

Set the polynomial equal to y to find the properties of the parabola. y=x2+6x−16 Complete the square on the right-hand side of the equation. More Steps (x+3)2−25 Reorder the right-hand side of the equation to match the standard form of a parabola. y=(x+3)2−25

OpenStudy (gnrfan):

@billj5

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