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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...
BK
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...
BK
Answered by Baran K. • Maths tutor
8763 Views

What does it take to make a 7 in HL Math?

A question that haunts every IB HL Math student day and night. Most students beleive that if they solve all past exams and practice book problems they should easily make a seven. That is absolutely not true....
YM
Answered by Youssef M. • Maths tutor
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X=4a+3b, If a is a two digit cube number and b is a two digit square number then what is the lowest possible value for X?

In order to find the lowest value for X we first need to find the lowest possible value for a and b. Let us start off with a: If a is the lowest possible cube number we can start by checking the first couple...
SI
Answered by Silje I. • Maths tutor
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Simplify 3!/5!

We call 3! 'three factorial' and 5! 'five factorial'. 3!=3x2x1 5!=5x4x3x2x1 So our fraction becomes: (3x2x1) / (5x4x3x2x1) = 6/120 Then dividing the top and bottom by 6 we get: 1/20
ME
Answered by Max E. • Maths tutor
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