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Mathematics 16 Online
OpenStudy (sabrinathebruja):

Find the real solutions of the equation by factoring. x^3 + 6x^2 + 25x + 150 = 0 I know the answer is -6 but can someone explain the process?

OpenStudy (sunnnystrong):

I'll try my best! so... \[x^3+6x^2+25x+150=0\] When factoring cubic equations --> split it in half. Factor the first two terms separately than the second two terms separately \[x^2(x+6)+25(x+6)=0\] ---> combine \[(x+6)(x^2+25)=0\]

OpenStudy (sabrinathebruja):

what happened to the 150?

OpenStudy (sunnnystrong):

@sabrinathebruja factored (: 25(x+6) ---> 25x+150

OpenStudy (sabrinathebruja):

so x3+6x2 became x2(x+6) and 25x+150 became 25(x+6) to make x2(x+6)+25(x+6) = 0?

OpenStudy (sabrinathebruja):

@sunnnystrong

OpenStudy (sunnnystrong):

yep... when factoring cubics you need to make sure the factored term in the () is the same so you combine --> \[(x^2+25)(x+6)\]

OpenStudy (irishboy123):

and they travel in conjugate pairs... \(x = -6\) and \( x =\pm i ~ 5\)

OpenStudy (sabrinathebruja):

so how do i get -6? @sunnnystrong

OpenStudy (sabrinathebruja):

@irishboy123 i is considered a real solution?

OpenStudy (sunnnystrong):

@IrishBoy123 thankk you!

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