Need help with Maths homework again please

[Friar]

This time its Solving equations

My 12 yr old daughter has an algebra work sheet.

as an example here is one of the questions

5x - 5 = 16 + 2x

I seem to remember something about moving stuff to the other side of the equals sign, which changes its sign, but thats about it.

Could someone run through the steps so that I understand what you would go through to solve this type of sum please.

Cheers guys

Friar

[Rattler]

group your "like" terms together; get the "x"'s on one side, and the numbers on the other, typically the "x"'s on the left equal to the number on the right.

for this one....

5x - 5 = 16 + 2x

1. Subtract 2x from both sides:

5x - 2x - 5 = 16 + 2x - 2x (the 2x's on the right now cancel each other out; they = 0)

3x - 5 = 16

2. Now, add 5 to both sides:

3x - 5 + 5 = 16 + 5

3x = 21

3. Now, you need to divide out the 3 on both sides...

3x/3 = 21/3

x = 7

I'll post a diagram that shows how this works if you need it - I find that understanding why this happens helps internalize the math rather than just "following the rules."

Cheers, mate!

PS - check the answer is correct by putting the 7 back in the original problem, and both sides should equal each other.

5x7 - 5 = 16 + 2x7

35 - 5 = 16 + 14

30 = 30

[Friar]

Thanks m8, I was hoping you would be available.

So if I think I understand it....

x - 4 = 41 - 4x

x + 4x - 4 = 41

x + 4x = 41 + 4

x + 4x = 45

5x = 45

x=9

9-4 = 41 - 4x9

5 = 41 - 36

5 = 5

would that be right, not sure on the method though !

Cheers.

[Rattler]

This is a 'newer' way of teaching algebra, called 'algebra tiles.' If it confuses, go back to just using the regular algebra notation.

[attachthumb=1]

[attachthumb=2]

[attachthumb=3]

[attachthumb=4]

Diagrams with balances also work well. Check out this website for help.

http://nlvm.usu.edu/en/nav/frames_asid_201_g_4_t_2.html

[Rattler]

Thanks m8, I was hoping you would be available.

So if I think I understand it....

x - 4 = 41 - 4x

x + 4x - 4 = 41

x + 4x = 41 + 4

x + 4x = 45

5x = 45

x=9

9-4 = 41 - 4x9

5 = 41 - 36

5 = 5

would that be right, not sure on the method though !

Cheers.

That way works perfectly fine, mate.

[BBloke]

Have you got any more Friar.

[Rattler]

Have you got any more Friar.

[BBloke]

Oh ek.

[Rattler]

Oh ek.

[BBloke]

I'll see how I go but a drawing may be required.

[Rattler]

I'll see how I go but a drawing may be required.

[BBloke]

WARNING: Unless you are Rattler I would stay well clear of this inane post!!!

Well, I did some drawings.

[BBloke]

Thats funny.. thats pretty much what my scrap pad looks like. LOL

[BBloke]

All thats just reminded me of the programming I did for Rog.

[Rattler]

Very nicely done, mate! You have a great talent for algebra. Your solution is exactly correct, and quite elegant. It's really well done. Congrats!

[Logos]

Sorry.

Too much in between. Also I flunked algebra. Number and letters in the same equation is dirty red communism. Oops. I shouldn't be here.

Later.

[Rattler]

Ah, bs. You're still a Dog. Post away!

Fly too, when you decide to un-exile yourself.

[BBloke]

Thanks Rattler

oh god.. I'm soooo sad

[Rattler]

Don't be sad; it's natural to feel wierd when you're a math-geek-prodigy. You're well above average in that regard mate, and it's only one of your talents!

Dang if you don't know your way around a computer too - must be some link there.....

Cheers, and have a good sleep - you'll have formulae running through your head all night long now!!!   

[Psycho]

When I was in High school, I said to myself, "when and where will I ever use this crap?"

[Rattler]

Glad to know those things are around to help my brother out if they need it....

[BBloke]

Thanks Rattler.

[Painless]

~S~ Colin M8,

This is the site I use to help Jonathan out with such perplexing homework:

www.themathpage.com/alg/rules-of-algebra.htm

Its really simple to follow ,(obviously ! LOL ), it also has lots of examples to try as you go along.

Hope that helps.

~S~ Brainless

[Friar]

thanks painless. we got it all sorted last night.

Many thanks one and all for your contributions

I love you guys...........

[Streak]

When I was in High school, I said to myself, "when and where will I ever use this crap?"