Factorise x^2 - 8x - 20
x^2 - 8x - 20
(x - 10)(x+2)
(Explanation and helping understanding) Remember the last 2 numbers must multiply to equal the last number in the question and add together to equal the middle number. See that the numbers at the end of each bracket multiply to equal 20 and add to equal 8. If you are unsure whether you have gotten the correct answer, expand what you have just made and see if it is the same as what is in the question.
CS
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