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A circle with centre C has equation x^2 + y^2 + 2x + 6y - 40 = 0 . Express this equation in the form (x - a)^2 + (x - b)^2 = r^2. Find the co-ordinates of C and the radius of the circle.

We can express the equation of any circle in the form (x - a)^2 + (y- b)^2 = r^2 . The centre of the circle is then the point (a, b) and its radius is r . If we multiply out the brackets in the equation abov...
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Answered by Baran K. • Maths tutor
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The line AB has equation 3x + 5y = 7. What is the gradient of AB?

The gradient of a line in the form y = ax + b, where a and b are some numbers, is the number a . So we need to get the equation 3x + 5y = 7 into the above form, with y on one side on its own! We first move t...
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Answered by Baran K. • Maths tutor
8925 Views

What are accents for?

Accentuation in Spanish is used to guide the reader into how a word is pronounced. The idea is that a word can be chopped into syllables, and the syllable with the accent in it will be the strongest one, or ...
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Answered by Mathilda B. • Spanish tutor
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What is evolution and why does it happen?

Evolution is a constant process that allows life forms to adapt to a changing environment. How does the environment change, though? Well, there are several sources of variation in every ecosystem. Variation ...
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Answered by Mathilda B. • Biology tutor
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How do I write about the background of a source?

Historical sources are an essential part of studying the past. Though can sometimes be confusing, there are lots of easy ways on how to break them down.The background of a source is essential to understand i...
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Answered by Ellen L. • History tutor
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