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17 votes
17 votes
Factorise and solve x^2 + 4x -21 = 0

User Yavanosta
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2 Answers

19 votes
19 votes

Answer:

(x+7)(x-4) x=-7,4

Explanation:

The factors of -21 that add up to 4 are 7 and -3, so put those as your two second values in your binomials and solve for x, in this case being the negative versions of the second term in the binomial

User TrapezeArtist
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2.9k points
9 votes
9 votes

Answer:

(x + 7) (x - 3)

Explanation:

Find 2 numbers that add to 4 and multiply to -21

(x + 7) (x - 3)

User Nsk
by
3.2k points