I can’t even do simple algebra anymore :(:(

[TheNinja]

A lot of the "problems people have with basic algebra" are actually "problems with fractions."

I learned this with my gf.

so 2/3L could be interpreted as
(L x 2)/3
or
L x (2/3)

so when you do L x (2/3) it becomes obvious that L times all of that again is

L squared x (2/3)

Now, to isolate L squared, you have to multiply both sides by 3/2, because

2/3 x 3/2 = 1

so that makes L squared times one, isolating it.

Now, all you have left is
3/2 x 864 = L squared

and at that point you just need reduce 3/2 x 864 and square root both sides to find L



so is a hammer!

Thank you for the explanation!!

So I guess if I wanted an easier equation it could be something like

L*(3*L)=864.

So in this case I could do L squared x 3 = 864 (Basically (L*3) x (L*L))
Or divide both sides by 3 to get
L squared = 288
L*L = 288
L = 288/L
Or basically the square root of 288.
So L is roughly 16.97

Now I gotta figure out how to do square root in my head

 

[drstrangelov]

I can’t really either, but I struggled and figured it out like:

864= x(1.5x)

then 864/1.5=x(x)

576=x(x)

x=24

width 24, length 36.

I think that’s right and know I would have been able to do that much, much faster when I was 14.

 

[General_Speckz]

Thank you for the explanation!!

So I guess if I wanted an easier equation it could be something like

L*(3*L)=864.

So in this case I could do L squared x 3 = 864 (Basically (L*3) x (L*L))
Or divide both sides by 3 to get
L squared = 288
L*L = 288
L = 288/L
Or basically the square root of 288.
So L is roughly 16.97

Now I gotta figure out how to do square root in my head

that would be correct if the width was equal to 3 times the length, but you said the length was 2/3 the width.

so that means

L = 2/3W
3/2 times L = W

because again we multiply by 3/2 to reduce the fraction on the W side to one because: 2/3 times 3/2 = 6/6 = 1)

L * (3/2 * L) = 864 is your version, corrected

your version works if L was 1/3 the W, though!

 

[TheNinja]

that would be correct if the width was equal to 3 times the length, but you said the length was 2/3 the width.

so that means

L = 2/3W
3/2 times L = W

because again we multiply by 3/2 to reduce the fraction on the W side to one because: 2/3 times 3/2 = 6/6 = 1)

L * (3/2 * L) = 864 is your version, corrected

Sorry.....I went away from the original question of Area and 2/3 of Length. I was more just talking about simplifying an equation in general. And I took out the fraction but that was making it even more difficult to grasp at first. Nothing to do with the original post.

So just a generic equation of like

A*(4*A)=1200 for example could be
A^2 / 4 = 1200 / 4
A^2 = 300
A = Square Root of 300
A=17.32

BUT I had to use a calculator to figure out Square Root. That's the part I"m missing in a generic simply equation now.

 

[supnmunm]

If it makes you feel any better, I can't even remember how to do short or long division on paper anymore. Doesn't help that I haven't had to use it in 10+ years but I still forgot probably 90% of what I learned in school.

 

[MikeMcMann]

w = 2/3 L.

A = L w = L (2/3 L) = 2/3 L^2.

L = (3/2 A)^(1/2)

L = (3/2 864 sq ft)^(1/2) = 36 feet

w = 2/3 36 feet = 24 feet.

Potato

My answer is potato

I am torn between these two very well thought out and instructive answers.

 

[PG29 red0 Jr]

[QUOTE="rj144, post: 158701633, member:

w = 2/3 36 feet = 24 feet.[/QUOTE]

Agreed

 

[MikeMcMann]

i have two female friends who are both doing very well in Real Estate who send me the exact same type of emergency text all the time.

"what is the percentage increase in price for this listing between sales".

So for example they are looking at a property that just sold for X ($1,000,000) that sold for Y ($800,000) three years ago.

Of course the equation is pretty basic (X-Y)Y
- (!,000,000 - 800,000) /800,000 = 25% increase in price

and of course if you reverse that saying it sold (X) $800,000 now but sold for (Y) $1MM, three years ago so what is the percent decrease:

- (Y-X)/Y - 20% drop in price


----------

So ya basic math still comes in useful, particularly in certain field for client edification.

 

[rj144]

This is all good but you could shorten the steps by going straight to W without calculating L first i.e.
W = ((2/3)*864)^(0.5)
W = 24 (feet)

Of course, but it's slightly more difficult to explain that way if someone doesn't understand math.

 

[General_Speckz]

Sorry.....I went away from the original question of Area and 2/3 of Length. I was more just talking about simplifying an equation in general. And I took out the fraction but that was making it even more difficult to grasp at first. Nothing to do with the original post.

So just a generic equation of like

A*(4*A)=1200 for example could be
A^2 / 4 = 1200 / 4
A^2 = 300
A = Square Root of 300
A=17.32

BUT I had to use a calculator to figure out Square Root. That's the part I"m missing in a generic simply equation now.

Apparently this video (timestamped) shows you how to do it for big numbers, but it looks like it would take a bit of practice:



I just Google "scientific calculator". shrug

 

[therealdope]

I struggled with an algebra question that was related to logarithmic functions with different bases that my daughter got as an assignment in her high school calculus class.

Would have been worse if I couldn't do it. Bad enough that I struggled (a bit).

 

[Streeter]

I went to Calc 4 in college n got at least a B in all of them. When my kid was a jr in his he asked me for algebra 2 help ...... I was clueless. Not my proudest parenting moment.

 

[n...not crazy]

Just draw an X on a sheet of paper and go from there.

 

[rj144]

I went to Calc 4 in college n got at least a B in all of them. When my kid was a jr in his he asked me for algebra 2 help ...... I was clueless. Not my proudest parenting moment.

WTF is Calc 4?

 

[Streeter]

WTF is Calc 4?

Calculus 4.

 

[rj144]

Calculus 4.

What do you do in Calc 4? Never heard of a Calc 4.

 

[D3THRONED]

Calculus 4.

Calc 1 = limits, derivatives, integrals
Cal 2 = limits, integrals by parts, remember lots of graphs and shit, taylor series
Calc 3 - XYZ version of calc 1

wtf is calc 4 lmao? only thing else I can think of is differential equations which is way different.

 

[MikeMcMann]

WTF is Calc 4?

At the Uni i went to and was in the Math program we had Calc 1, Calc 1 advanced, Calc 2, and advanced Calc 2, which most of just referred to as Calc 3.

- Calculus I
- Advanced Calculus I
- Calculus II
- Advanced Calculus II


If it would not have been awkward to refer to Adv Calc 1 as Calc 2, I think that would have been the students choice, meaning then we would have had up to Calc 4.

 

[MikeMcMann]

@D3THRONED ^^^

 

[EyeOfNewt]

What do you do in Calc 4? Never heard of a Calc 4.

Some unis separate cal 3 into 2 courses. One that deals with polar coordinates, quadric surfaces, limits and minima and maxima of functions of several variables. The second course deals with integration and more vector calculus (div, curl, etc.)