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I need help with a level maths!!

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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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=2.5x(15−x)2M=\frac{2.5x(15-x)}{2} ?

Start by multiplying both sides by 2.

What do you get?
Reply 2
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IonaNa
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Original post by BuryMathsTutor
M=2.5x(15−x)2M=\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
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?
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 172\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.
Reply 5
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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?
Reply 6
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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 172\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.
Original post by BuryMathsTutor
M=2.5x(15−x)2M=\frac{2.5x(15-x)}{2} ?

Start by multiplying both sides by 2.

What do you get?

How do you type equations like that?
Reply 8
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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
Reply 9
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IonaNa
OP
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Original post by BuryMathsTutor
It isn't.

What do you get if you multiply 172\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
??
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×21=2.5x(15−x)2×21M\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?
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
Reply 12
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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×21=2.5x(15−x)2×21M\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?image.jpg

Is this better, sorry I’m being so difficult I just really need to understand this..
image.jpg80.7KB
Reply 13
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IonaNa
OP
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Original post by BuryMathsTutor
Perhaps think of it as multiplying both sides by 2/1.

M×21=2.5x(15−x)2×21M\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?image.jpg

Is this better, sorry I’m being so difficult I just really need to understand this..
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)2M=2.5x(15-x)

You can multiply by 2 again if you like.
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)
Reply 16
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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)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
Reply 17
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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?
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 ax2+bx+c=0ax^2+bx+c=0
Reply 19
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IonaNa
OP
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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 ax2+bx+c=0ax^2+bx+c=0

So to put it all into the equation
2.5x^2 - 37.5x - 2M= 0??

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