Question:
Solve x^(2)-x-12
Methods:
We must factorise. Find factor pairs of -12;1,-12;-1,12;2,-6;-2,6;3,-4;-3,4. Out of the pairs, we must find the pair that will add up to -1 – this is because of the ‘-x’ part of the equation. The answer is 3 and -4. Now use this to factories; (x+3)(x-4). Check by expansion. Now make this equal to zero and solve for x.
Answer:
x = -3 x = 4
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