How do you factor $x^{2} - 2 x - 15 = 0$ $x^2-2x-15=0$ ?

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How do you factor $x^{2} - 2 x - 15 = 0$ $x^2-2x-15=0$ ?

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Answer 1 · 2016-09-17T15:38:54

$(x - 5) (x + 3)$ $(x-5)(x+3)$

Explanation:

$x^{2} - 2 x - 15 = 0$ $x^2 -2x-15=0$

Find factors of 15 which SUBTRACT (because of MINUS 15) to give 2.

$\to$ $rarr$ The factor pairs of 15 are: $1 \times 15 and 3 \times 5$ $1xx15 and 3xx5$

$\to 5 - 3 = 2 \to$ $rarr 5-3 = 2" "rarr$ so 5 and 3 are the factors we need.

The signs in the brackets will be DIFFERENT (because of MINUS 15)
- there must be more negatives, because of MINUS 2.
$\to$ $rarr$ the bigger factor will be negative

$(x - 5) (x + 3)$ $(x-5)(x+3)$

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How do you factor $x^{2} - 2 x - 15 = 0$ $x^2-2x-15=0$ ?

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How do you factor x^2-2x-15=0x2−2x−15=0x^2-2x-15=0 ?

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Explanation:

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How do you factor $x^{2} - 2 x - 15 = 0$ $x^2-2x-15=0$ ?