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If x^3 + 3x^2 – 10x = 0, indicate all the possible

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If x^3 + 3x^2 – 10x = 0, indicate all the possible [#permalink]  12 Jun 2017, 14:36
Expert's post
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Question Stats:

45% (01:08) correct 54% (00:59) wrong based on 51 sessions

If $$x^3$$ + $$3x^2$$ – 10x = 0, indicate all the possible values for the sum of any two solutions for x.

Indicate all that apply.

A) -10

B) -5

C) -3

D) -2

E) 0

F) 2

G) 3
[Reveal] Spoiler: OA

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Re: If x^3 + 3x^2 – 10x = 0, indicate all the possible [#permalink]  12 Jun 2017, 19:34
Here is what did on this question ->
x^3+3x^2-10x=0

x(x^2+3x-10)=0

One solution is x=0

Next ->
x^2+3x-10=0
x^2+5x-2x-10=0
x(x+5)-2(x+5)=0
x=2 or x=-5

Hence the solutions are => x=0,2,-5
Possible sums => -5,2,-3

Hence B,C,F
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Re: If x^3 + 3x^2 – 10x = 0, indicate all the possible [#permalink]  14 Jun 2017, 06:10
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Expert's post
Carcass wrote:

If $$x^3$$ + $$3x^2$$ – 10x = 0, indicate all the possible values for the sum of any two solutions for x.

Indicate all that apply.

A) -10

B) -5

C) -3

D) -2

E) 0

F) 2

G) 3

[Reveal] Spoiler: OA
B, C,F

Given: x³ + 3x² - 10x = 0
Factor out x to get: x(x² + 3x - 10) = 0
Factor quadratic to get: x(x + 5)(x - 2) = 0

So, x = 0, or x + 5 = 0, or x - 2 = 0
If x + 5 = 0, then x = -5
If x - 2 = 0, then x = 2

The 3 solutions are: x = 0, x = -5, and x = 2

Adding all 3 possible pairs of solutions, we get the following sums: -5, 2, and -3

[Reveal] Spoiler:
B, C, F

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Brent Hanneson – Creator of greenlighttestprep.com

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Re: If x^3 + 3x^2 – 10x = 0, indicate all the possible [#permalink]  11 Dec 2018, 17:47
the sum messed me up. extra careful when reading the question
Re: If x^3 + 3x^2 – 10x = 0, indicate all the possible   [#permalink] 11 Dec 2018, 17:47
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