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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
   
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It is very important when approaching a question like this, to not only consider the number of marks, but likewise the dates given. This question is worth 12 marks, so requires you...

(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 ...