simple math help

[Speedstack79]

<see picture attached>

 

 

 

how come when you simplify (x^2+h) + (2x^2+h) it is apparently 3x^2 + h and NOT 3x^2 + 2h.... how come the x^2 and the 2x^2 become 3x^2 but the h and the other h   do not combine to 2h??

[Godlygamer23]

Not sure what you're exactly referring to. When putting the problem into Wolfram Alpha, it comes out to be 3x²+2h. Because both terms are being added together, and they're both positive, your parenthesis drop and you simply combine the terms together.

 

@Speedstack79. Think about the Associative property.

[Ekpyrosis]

You're right, (x²+h)+(2x²+h) equals 3x²+2h, what makes you believe that it shouldn't?

I don't really undestand your attachment.

[ind3x]

(x^2+h) + (2x^2+h) => x^2+h + 2x^2+h) => x^2+2x^2+h+h =>3x^2 + 2h

[Speedstack79]

@ind3x  @Godlygamer23

 

You're right, (x²+h)+(2x²+h) equals 3x²+2h, what makes you believe that it shouldn't?
I don't really undestand your attachment.

the original equation is  if x is 2 and h is 4, then the answer should be 48 

 

if you plug in 2 and 4 into 3x²+2h you get 20 and not 48

[Godlygamer23]

@ind3x  @Godlygamer23

 

the original equation is  if x is 2 and h is 4, then the answer should be 48 

 

if you plug in 2 and 4 into 3x²+2h you get 20 and not 48

That's correct. Using Wolfram Alpha, they get the same answer. 20.

[Bene]

http://www.wolframalpha.com/input/?i=x%5E2+h%2B2+x%5E2+h

 

http://www.wolframalpha.com/input/?i=%28x%5E2%2Bh%29%2B%282+x%5E2%2Bh%29

[Speedstack79]

That's correct. Using Wolfram Alpha, they get the same answer. 20.

Screenshot_2015-08-29-17-42-10.png

Screenshot_2015

when I enter the equation enter wolfram ( http://www.wolframalpha.com/input/?i=x%5E2h+%2B+2x%5E2h ) it gives 2hx ²    which gives 48 if x = 2 and h = 4 ; which is what the original equation also gives... my question is why x²h + 2x²h  does not group to be 2h

[ind3x]

@ind3x  @Godlygamer23

 

the original equation is  if x is 2 and h is 4, then the answer should be 48 

 

if you plug in 2 and 4 into 3x²+2h you get 20 and not 48

 

if x=2 and h=4

x^2*h would be 4*4=16

2x^2*h would be 2*4*4=32

in total 48

 

you could simplify it to:

h(x^2+2x^2)

h(3x^2)

4(12)=48

 

This is the simplest i can make it

[ind3x]

-snip-

my question is why x²h + 2x²h  does not group to be 2h

Because it's two different terms.

Therefore you can't simply add it together (like i did wrongly in my first post)

You can simplify it as i do right above this post.

[Godlygamer23]

Your original expression was this: (x^2+h) + (2x^2+h)

 

Now it seems that you're changing the expression or becoming confused by your own post.

[Ekpyrosis]

when I enter the equation enter wolfram ( http://www.wolframalpha.com/input/?i=x^2h+%2B+2x^2h ) it gives 2hx ²    which gives 48 if x = 2 and h = 4 ; which is what the original equation also gives... my question is why x²h + 2x²h  does not group to be 2h

The text in your post and your attachment show different terms.

Is it "(x^2+h) + (2x^2+h)" we're talking about, or

"x^2*h+2x^2*h"?

[Speedstack79]

Because it's two different terms.

Therefore you can't simply add it together (like i did wrongly in my first post)

You can simplify it as i do right above this post.

ooh, I forgot how terms worked ;

@everyone who responded