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a) You area told that y is proportional to x2 and that when y = 75, x = 5. Find a formula for y in terms of x. y = x b) Find the value of y when x = 3. c) Find the value of x when y = 1200.

a) y is proportional to x^2, when x is 5, y is 75 Therefore: 75 = (something multiplied by) 5^2 75 = 3 x 25 Hence y = 3x^2 b) y = 3 multiplied by 3^2 = 27 c) 1200 = 3x^2 1200/3 = x^2 400 = x^2 Undo the squar...
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Answered by Kezia M. • Maths tutor
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Dipen and Nisha are planning their wedding reception. Nisha says, “I want to invite 70 guests.” Dipen says, “If we invite one-fifth fewer guests, we will save more than £500” Is Dipen correct? (Taken from Nov 2014 AQA Unit 2)

Need to calculate two things in order to answer the question: 1) Total cost of Nisha's 70 guests. 2) Total cost of Dipen's 'one-fifth fewer' guests. For Nishen: Total cost = £40 * 70 minus the 5% reduction =...
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Answered by Alex N. • Maths tutor
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Differentiate y=x*ln(x^3-5)

We can immediately see that more than differentiation rule will be needed here. The expression in question is the product of two smaller expressions, so the product rule may be useful. But to apply the produ...
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Answered by Nat N. • Maths tutor
7368 Views

Find the solutions to x^3+4x^2+x-5=1

These cubic equations are usually fairly simple once the method is known, firstly make the right hand side (RHS) equal to zero by subtracting 1 from both sides: x^3+4x^2+x-6=0 Now the next step is a quick bi...
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Answered by Luke H. • Maths tutor
5323 Views

What's the difference between the mean, median and mode?

The mean, median and mode are three types of averages which you will be asked about in your GCSE maths exam. The best way to learn maths is by by doing it or at least running through examples. E.g. Given the...
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Answered by Thomas K. • Maths tutor
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