Answers

2014-07-27T14:37:50+08:00
A "quadratic" is a polynomial that looks like "ax2+ bx + c", where "a", "b", and "c" are just numbers.For the easy case of factoring, you will find two numbers that will not only multiply to equal the constant term "c", but also add up to equal "b", the coefficient on the x-term. For instance:Factor x2 + 5x + 6.I need to find factors of 6 that add up to 5. Since 6 can be written as the product of 2and 3, and since 2 + 3 = 5, then I'll use 2 and 3. I know from multiplying polynomials that this quadratic is formed from multiplying two factors of the form "(x + m)(x + n)", for some numbersm and n. So I'll draw my parentheses, with an "x" in the front of each:(x       )(x      )Then I'll write in the two numbers that I found above:(x + 2)(x + 3)This is the answer:  x2 + 5x + 6 = (x + 2)(x + 3)This is how all of the "easy" quadratics will work: you will find factors of the constant term that add up to the middle term, and use these factors to fill in your parentheses.
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