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Factor completely: 15x^2 − 40x − 15.

User Feeeper
by
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-5(3+8x+3x^2) this was my answer I’m sorry if I’d gotten it wrong
User Paul Carlton
by
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4 votes

Answer:

The answer to your question is 5(x - 3)(x + 3)

Explanation:

15x² - 40x - 15

Multiply the first and the last term (15) x (-15) = -225

Find the prime factors of -225

-225 3

- 75 3

- 25 5

- 5 5

-1

Find two numbers that added gives -40 and multiply gives -40 using the prime factors:

These numbers are -45 ( 3 x 5 x 3) and 5

Write -40 as the addition of the numbers just found -40 = -45 + 5

Write the original polynomial using these numbers 15x² - 45x + 5x - 15

Factor by grouping 15x(x - 3) + 5(x - 3)

(x - 3)(15x + 5)

Factor by like terms the second term (x - 3)(5)(x + 3)

User Emre Kilinc Arslan
by
8.1k points

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