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Mathematics 18 Online
OpenStudy (quickstudent):

Can someone please check this for me? Factoring Sum of Cubes

OpenStudy (quickstudent):

hartnn (hartnn):

3a is incorrect

hartnn (hartnn):

which makes 3b and 3c also incorrect

OpenStudy (quickstudent):

Ok, let me review it a moment...

hartnn (hartnn):

sure, i was about to say, try to find the error on your own

hartnn (hartnn):

and the same mistake is done in 4. you correct one, you correct all!! :)

OpenStudy (quickstudent):

Hmmm, I don't see what's wrong there. Can you explain?

hartnn (hartnn):

length = 2t its cube = \( (2t)^3 = 8t^3 \)

hartnn (hartnn):

basically you forgot the brackets :P

OpenStudy (quickstudent):

Oh, okay. I'll try doing those again then :)

hartnn (hartnn):

sure, all 3 a,b,c and 4 a,b,c needs that correction. let me know when you're done, i'll review it again.

OpenStudy (quickstudent):

Here it is now, corrected :) @hartnn

hartnn (hartnn):

lets come to 3b now. \((2t)^3 + 12^3 = (2t+12)((2t)^2 - (2t)\times 12) +12^2 \) makes sense?

hartnn (hartnn):

i missed the last bracket \((2t)^3 + 12^3 = (2t+12)((2t)^2 - (2t)\times 12 +12^2)\)

hartnn (hartnn):

got that^^ ?

OpenStudy (quickstudent):

OK, I get it.

hartnn (hartnn):

so your answer for 3b should be \((2t+12)(4t^2 -24t +144)\)

hartnn (hartnn):

now for 3c, its (2t)^3 not (8t)^3 ... so (2*7)^3 + 12^3 = 14^3 +12^3 = .........

hartnn (hartnn):

same thing goes for 4b and 4c :)

hartnn (hartnn):

\((2t+12)(4t^2 -24t +144)\) ^^ that can be further factorized \(8(t + 6)(t^2 - 6t + 36)\)

OpenStudy (quickstudent):

OK, now I've correct 3 and 4 again.

hartnn (hartnn):

typing error in 4b

hartnn (hartnn):

everything else is correct :)

OpenStudy (quickstudent):

I've corrected that typo:) Thanks for helping me:)

hartnn (hartnn):

welcome ^_^

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