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The expected value of a discrete variable is defined as:

E(X) = ∑x*P(X=x) (for all possible values of x, in this case x = {1,2,3,4,5} ) 

(next, we will expand the summation and substitute in...

The factors of a number are all the numbers that divide into it, so the HCF of two numbers is the highest number that is a factor of both numbers. I'd work it out by create a list of all of the prime fact...

x²-9x-10=0

1. Find two numbers that add to equal -9 and mulitiply to equal -10
   
2. These numbers are -10 and 1 so this equation factorises to equal (x-10)(x+1)=0
   
...

(a) Gradient (m) = (y₂-y₁)/(x₂-x₁) = (10-4)/(1-(-2)) = 6/3 = 2

(b) General equation of a straight line: y = mx + c    (c = y-intercept)

For our st...

On first glance, this looks like it is going to be a quadratic equation, so let’s try and put it in the form ax² + bx + c = 0 which we can factorize. If we subtract 6 from each side, we end up ...