# anyone need help for maths? Watch

Exam tommorow and i'll be glad to help with your revision, so fire away.

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#2

Concerning graphical transformations...what's the difference between f(2x) and 2f(x) ?????

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#3

(Original post by

Concerning graphical transformations...what's the difference between f(2x) and 2f(x) ?????

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**chazer154**)Concerning graphical transformations...what's the difference between f(2x) and 2f(x) ?????

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f(2x) stretches (or squashes) it by 1/2 horizontally

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**chazer154**)

Concerning graphical transformations...what's the difference between f(2x) and 2f(x) ?????

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#6

I don't understand how to factorise fully - I can only do simple and I can't prove algebraically

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#7

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(Original post by

I don't understand how to factorise fully - I can only do simple and I can't prove algebraically

**Emilythorb**)I don't understand how to factorise fully - I can only do simple and I can't prove algebraically

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#9

**just in general do not understand like it completely confuseses me**

**for example: 4 girls , 6 boys in one class, whats the probability teacher choses two boys if he selects two students at random**

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#10

(Original post by

ok can you factorise 2x squared + 7x + 6?

**shwansalah**)ok can you factorise 2x squared + 7x + 6?

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#11

(Original post by

**miageogiaxxxx**)**just in general do not understand like it completely confuseses me****for example: 4 girls , 6 boys in one class, whats the probability teacher choses two boys if he selects two students at random**Add them all together first so 4+6=10 students in the class

this means: 4/10 girls 6/10 boys which you can simplify to 2/5 girls 3/5 boys.

So now you want the probability of getting boys

**and**then boys again.

If it's a probability of something

**and**something else you times them together.

So 3/5 times 3/5 = 9/25

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(Original post by

Hm I would probably say x ( x + 7 And then I'd be stuck

**Emilythorb**)Hm I would probably say x ( x + 7 And then I'd be stuck

then two numbers times to make 12 and plus to make 7

4 and 3 works,

therefore we substitute it back into the equation

2x squared + 4x + 3x+ 6 ,

we factorise 2x squared + 4x and 3x + 6 seperately,

2x squared + 4x, we can take out a 2x

so

2x(x+2)

3x+6 we can take out a 3 so 3(x+2)

so answer is (2x+3) and (x+2)

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#13

(Original post by

Hm I would probably say x ( x + 7 And then I'd be stuck

**Emilythorb**)Hm I would probably say x ( x + 7 And then I'd be stuck

so 2x

**²**+ 7x + 6 is a quadratic. This means you will have two brackets with x in. Because it's 2x

**²**you will have 2x in one and x in the other like this:

(2x ) (x )

Then you need to find two numbers with multiply to make the number on the end (6) and add/total to make the number in the middle (7). The best way to do this is to use two factors of the end number (6) and try them out. e.g. 3 and 2.

Because the end number of the equation is positive (2x

**²**+ 7x

**+ 6**) the two numbers you picked will go into the bracket as positive like this:

(2x + 2) (x + 3)

If you expand this however you get 2x

**²**+ 6x + 2x + 6 which is 2x

**²**+ 8x + 6.

You have made the 3rd number but not the 2nd.

If you try switching the numbers like this:

(2x + 3) (x + 2)

It expands to 2x

**²**+ 4x + 3x + 6 which is 2x

**²**+ 7x + 6, the original equation.

So (2x + 3) (x + 2) is the factorised equation.

Hope this made sense

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#14

(Original post by

A number 'squared' is written as 'x^2' btw. (edit: think I managed to do a squared symbol though)

so 2x

(2x ) (x )

Then you need to find two numbers with multiply to make the number on the end (6) and add/total to make the number in the middle (7). The best way to do this is to use two factors of the end number (6) and try them out. e.g. 3 and 2.

Because the end number of the equation is positive (2x

(2x + 2) (x + 3)

If you expand this however you get 2x

You have made the 3rd number but not the 2nd.

If you try switching the numbers like this:

(2x + 3) (x + 2)

It expands to 2x

So (2x + 3) (x + 2) is the factorised equation.

Hope this made sense

**aadil10**)A number 'squared' is written as 'x^2' btw. (edit: think I managed to do a squared symbol though)

so 2x

**²**+ 7x + 6 is a quadratic. This means you will have two brackets with x in. Because it's 2x**²**you will have 2x in one and x in the other like this:(2x ) (x )

Then you need to find two numbers with multiply to make the number on the end (6) and add/total to make the number in the middle (7). The best way to do this is to use two factors of the end number (6) and try them out. e.g. 3 and 2.

Because the end number of the equation is positive (2x

**²**+ 7x**+ 6**) the two numbers you picked will go into the bracket as positive like this:(2x + 2) (x + 3)

If you expand this however you get 2x

**²**+ 6x + 2x + 6 which is 2x**²**+ 8x + 6.You have made the 3rd number but not the 2nd.

If you try switching the numbers like this:

(2x + 3) (x + 2)

It expands to 2x

**²**+ 4x + 3x + 6 which is 2x**²**+ 7x + 6, the original equation.So (2x + 3) (x + 2) is the factorised equation.

Hope this made sense

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#15

(Original post by

I understand all of this but I don't understand how you managed to get it back to 7x??

**Emilythorb**)I understand all of this but I don't understand how you managed to get it back to 7x??

When you expand it you have to multiply all the left side by all the right side:

2x X x = 2x

**²**

2x X 2 = 4x

3 X x = 3x

3 X 2 = 6

so you have 2x

**²**+ 4x + 3x + 6

The '4x + 3x' simplifies to '7x'

so you get 2x

**²**+ 7x + 6

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#16

(Original post by

Exam tommorow and i'll be glad to help with your revision, so fire away.

**shwansalah**)Exam tommorow and i'll be glad to help with your revision, so fire away.

I know how to regular ones that have a single x^2 but when they're like this with more than one x^2 then I have no idea. Can you link me to some help or explain this for me?

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2x squared - 7x+3

FIRST, you do the first number times the end number, ( 2 TIMES 3= 6)

SECONDLY, two numbers that times to make 6 and plus to make -7, the answer is -6 and -1

THRIDLY, the expression was 2x squared -7x + 3,

NOW it becomes 2x squared -6x -1x +3 , ( we split the -7x into -6x and -1x)

NOW we factorise each part seperately

so we first factorise 2x squared -6x which is 2x(x-3)

Then we factorise the -1x + 3 which is -1(x-3)

which becomes (2x-1) and (x-3) which is ur final answer

FIRST, you do the first number times the end number, ( 2 TIMES 3= 6)

SECONDLY, two numbers that times to make 6 and plus to make -7, the answer is -6 and -1

THRIDLY, the expression was 2x squared -7x + 3,

NOW it becomes 2x squared -6x -1x +3 , ( we split the -7x into -6x and -1x)

NOW we factorise each part seperately

so we first factorise 2x squared -6x which is 2x(x-3)

Then we factorise the -1x + 3 which is -1(x-3)

which becomes (2x-1) and (x-3) which is ur final answer

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(Original post by

How do I factorise equations such as 2x^2-7x+3

I know how to regular ones that have a single x^2 but when they're like this with more than one x^2 then I have no idea. Can you link me to some help or explain this for me?

**joe4234**)How do I factorise equations such as 2x^2-7x+3

I know how to regular ones that have a single x^2 but when they're like this with more than one x^2 then I have no idea. Can you link me to some help or explain this for me?

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#19

(Original post by

Okay so first thing about the probabilities of each one just once.

Add them all together first so 4+6=10 students in the class

this means: 4/10 girls 6/10 boys which you can simplify to 2/5 girls 3/5 boys.

So now you want the probability of getting boys

If it's a probability of something

So 3/5 times 3/5 = 9/25

**aadil10**)Okay so first thing about the probabilities of each one just once.

Add them all together first so 4+6=10 students in the class

this means: 4/10 girls 6/10 boys which you can simplify to 2/5 girls 3/5 boys.

So now you want the probability of getting boys

**and**then boys again.If it's a probability of something

**and**something else you times them together.So 3/5 times 3/5 = 9/25

If you don't simplify it, just so it's clearer to see:

so 4/10 girls, and 6/10 boys

P(boy) on the first choice = 6/10

but P(boy) on second choice (assuming a boy was chosen the first time) would be 5/9 as one boy has been picked so cannot be picked again?

So the overall probability would be 5/9 x 6/10, which is 1/3

Sorry if this is over complicating stuff

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#20

Rearrange this equation?

P=n²+a/n+a -------->>> Rearrange this equation to make a the subject

Help please!!

I got a=n^2/pn+p-1 is it correct?

P=n²+a/n+a -------->>> Rearrange this equation to make a the subject

Help please!!

I got a=n^2/pn+p-1 is it correct?

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