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33 votes
I need help on this and I don't know how to do this.

Please Help

I need help on this and I don't know how to do this. Please Help-example-1
I need help on this and I don't know how to do this. Please Help-example-1
I need help on this and I don't know how to do this. Please Help-example-2
User Krassi
by
2.8k points

2 Answers

15 votes
15 votes

Answer:

Blank 1: -8

Blank 2: 3

Explanation:

Sorry if i'm late on this but it is the same X method concept. -8 and 3 add up to get -5, and they multiply to get -24

User SLendeR
by
2.9k points
16 votes
16 votes

9514 1404 393

Answer:

  • -8, 3
  • 6, -5

Explanation:

This sort of pattern is used in the factoring of trinomials. Typically, the top quadrant holds the product you're trying to factor. The bottom quadrant holds the sum of the factors. The factors appear on the left and right in no particular order.

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1) You're looking for factors of -24 that have a sum of -5. It can be useful to simply list the factor pairs. Since you want a negative sum, you may want to start with the most negative factors and work up from there.

-24 = (-24)(1) = (-12)(2) = (-8)(3) = (-6)(4)

The sums of these factor pairs are -23, -10, -5, -2. Obviously, the pair we're interested in is the one with a sum of -5: (-8) +(3).

So, the left- and right-quadrants are filled with -8 and 3.

Blank 1 = -8

Blank 2 = 3

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2) You are given the factors, so all you need to do is form the product and sum.

Blank 1 = (-3)(-2) = 6

Blank 2 = (-3) +(-2) = -5

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Additional comment

Any sort of factoring is much easier to do if you have memorized your multiplication tables, preferably through 12×12. It is also helpful if you're familiar with divisibility rules—at least for single-digit numbers. I've seen college students struggle trying to do factoring using a calculator. It's not pretty. Many folks learn their times tables up to 10×10 by the end of 3rd grade.

User Steven Williams
by
2.8k points