Factor x² − 5x − 36
Worked out line by line the way a teacher would write it.
Answer
| Factored form | (x − 9)(x + 4) |
Step-by-step solution
3 steps-
1 Givenx^{2} - 5 x - 36
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2 Find two numbers whose product is c = -36 and whose sum is b = -5
The goal is to write x² + bx + c as (x + p)(x + q). Multiplying that out gives x² + (p + q)x + p·q, so p and q must multiply to c = -36 and add up to b = -5.
List the pairs of numbers whose product is -36, with their signs, and pick the pair whose sum is -5.
(-9) \cdot 4 = -36,\qquad (-9) + 4 = -5 -
3 Factored form\left(x - 9\right) \left(x + 4\right)
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