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Factor this polynomial completely x2 - x - 20

User MartinF
by
8.4k points

2 Answers

9 votes

Answer:

(x +5) (x -4)

Explanation:

Factors of 20:

1,20

2,10

4,5

4 and 5 combine to create 1

+5 -4 = 1

(x +5) (x -4)

User Mohd Sher Khan
by
7.8k points
2 votes

Answer:

(x+4)(x-5)

Explanation:

We can look at it by thinking of two numbers, that add up to -1 and multiply to -20. We can first do this by looking at factors of -20, which are 1, -20, -1, 20, 2, -10, -2, 10, and so on. After looking through it, we can notice that -5 and 4 added equal -1, and when multiplied equal to -20, so they work. So, we factor to (x+4)(x-5)

User Narcolessico
by
8.3k points

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