IonaNa
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Right so I have a question that don’t understand

So we have to put this equation into the quadratic formula I hope someone can help me quick

M=2.5x(15-x)
2

That’s to divide by two after!!
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Plücker
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(Original post by IonaNa)
Right so I have a question that don’t understand

So we have to put this equation into the quadratic formula I hope someone can help me quick

M=2.5x(15-x)
2

That’s to divide by two after!!
M=\frac{2.5x(15-x)}{2} ?

Start by multiplying both sides by 2.

What do you get?
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IonaNa
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(Original post by BuryMathsTutor)
M=\frac{2.5x(15-x)}{2} ?

Start by multiplying both sides by 2.

What do you get?
Okay you’ll get 5x(30-2x)? Is that’s right
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Muttley79
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(Original post by IonaNa)
Okay you’ll get 5x(30-2x)? Is that’s right
No - what is 1/2 x 2?

Where has M gone?
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Plücker
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(Original post by IonaNa)
Okay you’ll get 5x(30-2x)? Is that’s right
It isn't.

What do you get if you multiply \frac{17}{2} by 2?

You don't get 34/4.

34/4 = 17/2.

Have another try and don't forget to include both sides of the equation.

Think of 2 as 2/1 if you find that it helps.
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IonaNa
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(Original post by Muttley79)
No - what is 1/2 x 2?

Where has M gone?
Okay so half times Two equals 1
and so M x 2 is 2M?
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IonaNa
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So I’d i times everything from the equation by 2 it’ll be

2M = 5x(30 - 2x)
4


(Original post by BuryMathsTutor)
It isn't.

What do you get if you multiply \frac{17}{2} by 2?

You don't get 34/4.

34/4 = 17/2.

Have another try and don't forget to include both sides of the equation.

Think of 2 as 2/1 if you find that it helps.
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Soul Wavel3ngth
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(Original post by BuryMathsTutor)
M=\frac{2.5x(15-x)}{2} ?

Start by multiplying both sides by 2.

What do you get?
How do you type equations like that?
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IonaNa
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(Original post by IonaNa)
Okay so to times all parts of the equation by 2 would be 2M=5x(30-2x)4?
(Original post by Muttley79)
No - what is 1/2 x 2?

Where has M gone?
Okay so 1/2 x2 is 1
and If you did M x 2= 2M
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IonaNa
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(Original post by BuryMathsTutor)
It isn't.

What do you get if you multiply \frac{17}{2} by 2?

You don't get 34/4.

34/4 = 17/2.

Have another try and don't forget to include both sides of the equation.

Think of 2 as 2/1 if you find that it helps.
Okay so to times all parts of the equation by 2 would be
2M=5x(30-2x)
4
??
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Plücker
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(Original post by IonaNa)
Okay so to times all parts of the equation by 2 would be
2M=5x(30-2x)
4
??
Perhaps think of it as multiplying both sides by 2/1.

M\times \frac{2}{1}=\frac{2.5x(15-x)}{2} \times \frac{2}{1}

The purpose of this is to cancel out the 2 in the denominator of the right hand side of the equation.

What would the next line be?
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Plücker
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(Original post by Soul Wavel3ngth)
How do you type equations like that?
You can do it using LaTeX. The guide is here: https://www.thestudentroom.co.uk/help/latex
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IonaNa
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(Original post by BuryMathsTutor)
Perhaps think of it as multiplying both sides by 2/1.

M\times \frac{2}{1}=\frac{2.5x(15-x)}{2} \times \frac{2}{1}

The purpose of this is to cancel out the 2 in the denominator of the right hand side of the equation.

What would the next line be?Name:  image.jpg
Views: 21
Size:  78.4 KB
Is this better, sorry I’m being so difficult I just really need to understand this..
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IonaNa
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(Original post by BuryMathsTutor)
Perhaps think of it as multiplying both sides by 2/1.

M\times \frac{2}{1}=\frac{2.5x(15-x)}{2} \times \frac{2}{1}

The purpose of this is to cancel out the 2 in the denominator of the right hand side of the equation.

What would the next line be?Name:  image.jpg
Views: 21
Size:  78.4 KB
Is this better, sorry I’m being so difficult I just really need to understand this..
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Plücker
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(Original post by IonaNa)
Is this better, sorry I’m being so difficult I just really need to understand this..
You're not being difficult at all.

It's not quite right.

Multiplying both sides by 2 will give you 2M=2.5x(15-x)

You can multiply by 2 again if you like.
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Muttley79
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(Original post by IonaNa)
Is this better, sorry I’m being so difficult I just really need to understand this..
On the right hand side the '2' on the numerator 'cancels' the '2' on the denominator so you should just have 2.5x(15 - x)
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IonaNa
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(Original post by BuryMathsTutor)
You're not being difficult at all.

It's not quite right.

Multiplying both sides by 2 will give you 2M=2.5x(15-x)

You can multiply by 2 again if you like.
Oh i see you need to get rid of the denominator
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IonaNa
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(Original post by Muttley79)
On the right hand side the '2' on the numerator 'cancels' the '2' on the denominator so you should just have 2.5x(15 - x)
Oh I get unit now.. what’s the next step?
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Plücker
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(Original post by IonaNa)
Oh I get unit now.. what’s the next step?
If you prefer to be working with integers you could now multiply both sides by 2 again. After that, bring all your terms to one side so that you have something of the form ax^2+bx+c=0
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IonaNa
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(Original post by BuryMathsTutor)
If you prefer to be working with integers you could now multiply both sides by 2 again. After that, bring all your terms to one side so that you have something of the form ax^2+bx+c=0
So to put it all into the equation
2.5x^2 - 37.5x - 2M= 0??
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