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Factor the expression 4x^2 - 12x - 7

1 Answer

6 votes

Answer:

(2x+1) (2x-7)

Explanation:

Multiply the coefficient of the first term by the constant 4 • -7 = -28

Find two factors of -28 whose sum equals the coefficient of the middle term, which is -12

( -28 + 1 = -27

-14 + 2 = -12 )

Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -14 and 2

4x2 - 14x + 2x - 7

Add up the first 2 terms, pulling out like factors :

2x • (2x-7)

Add up the last 2 terms, pulling out common factors :

1 • (2x-7)

Add up the four terms :

(2x+1) • (2x-7)

User Eric Caron
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