Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Pages: **1**

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

HI,

I am very weak in match, i have equation like

1. 3x-2y=1 h

2. 3x+y = x+3

Please help

Lokesh

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 105,718

Hi;

What is that h doing there?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.****No great discovery was ever made without a bold guess. **

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

i m doing set theory

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 105,718

I do not understand, aren't you solving a simultaneous set of linear equations? What has that to do with set theory? Is that h a variable?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.****No great discovery was ever made without a bold guess. **

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

quiz is this . find x and y if (3x+y, x-1) = (x+3, 2y-2x)

sorry h is mistake , h is nothing

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

this question is from ordered pairs, so that first i have to find x and y

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 105,718

I am getting x = 1 and y = 1.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.****No great discovery was ever made without a bold guess. **

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

yes, perfect, is there any method or something else to find value of x and y?

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 105,718

There are several methods:

Form the simultaneous set:

Do you know how to solve that?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.****No great discovery was ever made without a bold guess. **

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

no, i don't know

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 105,718

Clean this one up a bit by subtracting x from both sides.

Clean up the second one

Add 2x to both sides

Subtract 2y from both sides.

Add one to both sides

We now have

Did you follow up to here?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.****No great discovery was ever made without a bold guess. **

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

how do you think what to add or not?

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

ya i got it till here, but what next to find x and y?

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 105,718

how do you think what to add or not?

Just trying to get it into the form of all the variables on the left and all the numbers on the right so we can make the next bunch of moves.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.****No great discovery was ever made without a bold guess. **

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

ok, but what will be the next step to find x value?

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 105,718

We would like to subtract or add the bottom equation from the top one and make one variable disappear. But when I do that 2x - 3x = x, that did not disappear and y + (-2y) = y so no luck there either.

If I multiply the top equation by 3 I get

Now if I multiply the second equation by 2 I get

So I have changed the equations again to

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.****No great discovery was ever made without a bold guess. **

Offline

**lokitwister****Member**- Registered: 2013-01-31
- Posts: 10

Thanks, here i will find y

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 105,718

Can you finish now or do you want me to do more?

Where did he go?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.****No great discovery was ever made without a bold guess. **

Offline

Pages: **1**