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Solve the simultaneous equations: (1) x^2 + y^2 = 25 and (2) y - 3x = 13

Sub (2) y = 13 + 3x into (1)x^2 + (13 + 3x)^2 = 25x^2 + 169 + 39x + 39x + 9x^2 = 2510x^2 + 78x + 144 = 05x^2 + 39x + 72 = 0 (/2)572 = 360 - need ab=360 such that a+b=39a = 24 b = 155x^2 + 24x + 1...

Answered by Meghna M. • Maths tutor

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Square ABCD has length (x+3)cm and area 10cm^2. Show x^2 + 6x = 1

First sketch square ABCD. Split length into 3cm and then xcm for side AB and the same for side AD. Split the area of this square into 4 segments (a, b, c and d) such that a is a 3cm by 3cm square, b and c...

Answered by Meghna M. • Maths tutor

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Henry invest £8000 in youtube at a compound interest rate of 2% per year. He wants to earn more than £500 interest. Work out the least time, in whole years, that this would take?

Each year his money will increase by 2%, meaning he will get 102% of his money from the previous year. This can be written as 1.02. After n years, he will make 8000 x 1.02 ⁿ. Calculate this for...

Answered by Gillian L. • Maths tutor

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When should you use the sine rule and when should you use the cosine rule?

The sine rule can be used when we either know:a) the length of two sides A and B and an angle that is not the corner where A and B meetb) two angles and the length of one side
The cosine rule can be ...

Answered by Joseph B. • Maths tutor

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