Algebra SAT MATH Problem NLC

[prishc206]

Toughest? TOUGHEST?

Dude I'm 8th grade an I did this in less than a freaking minute >.<

Just saying... but I'm asian :P

[TH3PANDA8094]

so wait what's the answer?

[felicity12100]

this is so easy to solve

[KingKang094]

Square root both sides:

(x+y)-(x-y)>/=+/-5 Y cannot be negative, as the inequality shows, therefore:

(x+y)-(x-y)>/=5

Simplify:

x+y-x-(-y>/)=5 : 2y>/=5 : y>/=2.5

I thought that method would be much easier and more time efficient.

[brightlessshade]

HE GOT 710 WTF BE PROUD

[justin9816]

ehhh I'm more into a social studies person

[WhatTheTwinky]

Does this cost money to call your hotline for explainations

[yourit311]

That was a good math problem...I really wish I was this good with numbers..

[Thejeter5770]

umm.....  fish=duh

[shianara3]

boring



[TheAllTechInOnePlace]

just put a zero inplase of the y because its the least amount u can get and colculat !! im 15 and know that what are u stupid ?! (x+0)2-(x-o)2 y=0

[moneymaker8815]

im 13 and going into 8th grade.I clicked this video because i wanted to see if i could get it. Originally I thought i couldnt,but with you explaining it,i think i got it.thank you.But luckily i dont have to take this for some time to come.

[Motordirt1]

dude i check all of your comment and t seem that you have anger management

[Motordirt1]

Can do like dowloadable notes plz

[Motordirt1]

you seem to teach good stuff to bad i go to french school

[Ryuuusa]

You dont have to take it as "the mid point "theory you quoted for X and Y.

It clearly says in the question taht ,

0<= x <= Y

it says x can be equal to y hence u can put xy= y squared.

[MrSuperbomb]

fart teacher

[FERGIOUSNESSIOUS]

2.5 just obvious

[mathproblems]

how and why?

[RyanxHurst]

@mathproblems

What he did was square root both sides. Therefore 2y >/ 5

[marangis]

theres an easier and different appoach to do this problem. just square root both sides of the equation solve for y and u kno why is great than 0 so it cant be the -2.5 but has to be the positive 2.5. done

[fandangofandango]

good problem

[grandtheftauto5000]

math sucks and so does school

[diggy126]

so y r u watching dis (little kids these days)

[mathproblems]

THEN FLIP HAMBURGERS

[AmericanKillSquad]

i love teachers

[PedroPistons]

Not hard, You just Need to know the basics of algebra, and theres no problem. But might be hard to some people.

[domsworkCN]

uhhhh what does quanity mean??? lol

[aahmed7861]

what da fuck this is math which i used to do in 4th class....bull shit basic algebra

[shemeferraj]

i am in fifth and can solve this stupid americans

[blockfrom3062]

Don't be nasty. My students can solve this problem is 5-10 seconds. If you can't, email me and I'll explain how it can be solved that quickly. Unfortunately this instructor does not teach methods that can be used to solve classes of problems. He do not appear to teach general approaches. If he shows you how to solve one problem and, of couse, that problem will not appear on the SAT, has he really helped you?

[Ren520]

what's ur solution? i'm curious :)

[blockfrom3062]

I can't write solution in under 500 words. Email me and I'll returrn an email with the solution.

[anthonyac2]

i dont think that guys american

[lucasdaudt22]

Thats y hes smart.

[HunniiBunniz]

hard!!!!!!

[zh1412]

?? wad... its managable imo....

[ligosss]

too easy

[1QuitPking]

fake.

[Yungsta187]

fake

[zer0gravity0]

im in 7th and im dum as hell XD

[hotty6745]

wha? i'm only 11 (: and this was on reccomended for you. LOLWTF.

[lamez0r]

this is such an easy problem, i could do this in 6th grade, what's wrong with you americans

[maplestoryjoe]

its 69

[Tonygoescrazy]

That's simple

[yomammaonastick]

if i really gave a crap i culd figure this out

[S1lentMayhem]

it can be done. just use distributive property.

[Nanumir]

you are the greatest

[lowIQ04]

subliminal message pause at :58

[xLoGDx]

him looking out of the window?

[jayskingdomthemepark]

WITW!!!!

[blindironman202]

I figured that out and I'm in 7th grade. What what I did was factor both parts of (x+y)^2-(x-y)^2, so

(x^2 + y^2 +2xy)+ (x^2 + y^2 -2xy)=

2x^2 + 2y^2= 4y^2 because the smallest value of y would be when x=y equal the same since it's equal or greater and then you have 4y^2=25 so squareroot both sides and you get 2y=5. Divide by 2 and you get 2.5, the same answer that he gives. I don't get what he does at the beginning though.

[FrozenFox87]

im in grade 6 and i dont understand anything you just said.

[yomammaonastick]

ummm duh!!

[FrozenFox87]

If you haven't noticed, I was replying to blindironman202's comment.

[CorysVidz]

Wow, You either got that answer off your mom , or your not Grade 7. Im in grade 7, and That kind of shit isnt until Grade 8/9. Nice try though, bud.

[blindironman202]

I was in fact, in 7th grade when I answered, but now I'm in 8th. Also, when I was in 7th grade, I was already learning Algebra 2 so... Anyways, there was a mistake in what I wrote because I was rushing. Factor both parts of (x+y)^2-(x-y)^2, so

(x^2 + y^2 +2xy)- (x^2 + y^2 -2xy)=

2x^2 - -(2y^2)= 4y^2 because the smallest value of y would be when x=y equal the same since it's equal or greater and then you have 4y^2=25 so squareroot both sides and you get 2y=5. I put a plus sign instead of a -

[MrGuarono]

Dude, my teacher gave me this problem in 2nd grade and I got this right! But now I hate math :P

[qu4zu000]

i got that all right and im in grade 10

[jellycakedude001]

lol, im in grade six and im sitting here going wtf?

[evilandcute]

your wrong...srry bout tht..

[mario11168]

My brain hurts.. a lot

[detry322]

Come on!!!! I took the SAT as a sixth grader and got this problem right!!!!!!!!!!!!

Answer is A or 1.25

[erikiscool250]

i had no idea what he was talking about haha

[mathproblems]

No bidg loss OK?

[erikiscool250]

ok. thats so hard

[fionathatsme]

i cant believe this is a difficult question i wish we had ones like it.. its just factorising... thats like a part A

[muhdimustafasharif]

i didn't understand u man example do more examples

[grgfrg7]

Buddy I'm in gr. 10 and i can figure that out pretty easily

[qu4zu000]

yeah me too *high five*

[gibzie]

well i got y=0.4

[blockfrom3062]

Some of my students do this problem in under 5 secs. (x+y)squared - (x-y)squared is 4xy. Since y >= x we have 4 y squared >= 4xy >= 25/4. y >= 5/2 so the least value is 5/2. An SAT math student knows how to expand binomials quickly.

[kurt872]

This is good up until the explanation of why x=y. This was more assertion than justification.

Here's how I see it: since y>=x, it follows that y^2>=xy. Since we have xy>=25/4, it follows (by the transitive property) that y^2>=25/4. This implies y>=5/2, making 5/2 the least possible value of y such that (x,y) is a solution to the original inequality. (Check: x=y=5/2 is a solution, so 5/2 is indeed the minimum such value of y.)

[r0ji]

thank you kurt for this nice proof, I didn't buy the "midpoint" assertion either :)

[kurt872]

This explanation is pretty good, except for the justification of x as the midpoint between 0 and 5. This was more assertion than anything else; I didn't buy the justification. (Also, the diagram makes it look like you're choosing x to be (1/2)*y, which is a little confusing.)

[titanas2]

least y = 25x/4

[booogiepop]

i did it in a completely different way

i squared rooted the whole formula and got 2y = 5 and from there I got 2.5

Your technique completely confused me, but did i do it right or am i just lucky this time?

[mathproblems]

how did u get 2y when you square root the whole formula ? You get Sqrt(4xy)=5 and not 2y=5. You are totally wrong but you got lucky may be because you knew the answer and try to fit it somehow. this is the hard problem

[GrimReaper1169]

(x+y)²-(x-y)²≧25➛(x+y)-(x-y)≧5­➛2y≧5➛y≧(5/2)

I believe that is how he, booglepop, got the answer. I'm not sure if this is "legal" to do though. Anyway, legal or not this is sure as hell easier than what the guy demonstrated. He didn't use the FOIL system, so whatever he did use was confusing to the people, including myself.

[kurt872]

The square root of the left-hand side is *not* (x+y) - (x-y). Square roots do not distribute across sums.

You made a mistake and got lucky. His technique confused you don't know algebra.

[kurt872]

Oops - I meant, "His technique confused you *because you* don't know algebra. (Rather like how I am confusing because I don't know how to proofread. :)

[booogiepop]

i did it in a completely different way, i square-rooted the whole formul and got 2y = 5 and from there i got 2.5

Your way completely confused me! I kept on watching the video, but I still don't get it. But is my way a good way or am I just lucky this time?

[vinod43]

this is very smart and short way SATway!!!!

[noobcola]

Ohhh, I see what I did wrong. I got to the xy=25/4 part, but I forgot to find the least possible value of Y.

Thank you very much for your time!