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With a more wordy question like this, it is always best to break it up and write down all of the key pieces of information. So we want to work out the probability of picking: white AND white, OR, black AN...

The first step is to find a common denominator. Since x^2-9 can be expanded to (x-3)(x+3) and 1/(3-x) can be written as -1/(x-3), we can see that all the terms contain either (x-3), (x+3), or both. Theref...

x^2+4x-5=0(x+2)^2-(2)^2-5=0subtract 2^2 as (x+2)^2 = x^2+4x+4 when we want x^2+4x(x+2)^2-4-5=0(x+2)^2-9=0(x+2)^2=9square root both sidesx+2=+/-3x=-2+/-3x=-2+3 or x=-2-3x=1 or x=-5

To calculate the answer to this question we need to know the formula for the area of the circle. The area of a circle is:

A = Pi x r^2

The value of r is given in the question; r = 12. We the...

This was the final question in AQA's 2011 non-calculator paper, and most top candidates will be looking to score all 5 marks that are on offer. Our usual technique for simultaneous equations isn't going t...