Factorizing cubed expressions

[Mathdabbler]

I am struggling with the factorization of the above. It seems pretty hit and miss and I am getting the wrong middle term in the second trinomial. It’s a problem on almost all the cubed factorization I am doing. I’ve tried juggling the signs of the terms but clearly I do not have the process right. Can someone point me in the right direction? (I’m using Schaum’s Intermediate Algebra page 61 exercise 2.20.

 

[Deleted member 4993]

I am struggling with the factorization of the above. It seems pretty hit and miss and I am getting the wrong middle term in the second trinomial. It’s a problem on almost all the cubed factorization I am doing. I’ve tried juggling the signs of the terms but clearly I do not have the process right. Can someone point me in the right direction? (I’m using Schaum’s Intermediate Algebra page 61 exercise 2.20.

View attachment 13626

Third line in your response is incorrect. Correct formula for factorizing "sum of cubes" is

a³ + b³ = (a + b) * (a² - a*b + b²)

Fix your work accordingly and you will get book's answer.

 

[pka]

I am struggling with the factorization of the above. It seems pretty hit and miss and I am getting the wrong middle term in the second trinomial. It’s a problem on almost all the cubed factorization I am doing. I’ve tried juggling the signs of the terms but clearly I do not have the process right. Can someone point me in the right direction? (I’m using Schaum’s Intermediate Algebra page 61 exercise 2.20.

Look at this webpage. You can use to check other answers.

 

[Mathdabbler]

Third line in your response is incorrect. Correct formula for factorizing "sum of cubes" is

a³ + b³ = (a + b) * (a² - a*b + b²)

Fix your work accordingly and you will get book's answer.

Thanks - I’ll try that.

 

[Steven G]

I am struggling with the factorization of the above. It seems pretty hit and miss and I am getting the wrong middle term in the second trinomial. It’s a problem on almost all the cubed factorization I am doing. I’ve tried juggling the signs of the terms but clearly I do not have the process right. Can someone point me in the right direction? (I’m using Schaum’s Intermediate Algebra page 61 exercise 2.20.

View attachment 13626

Although your last line is wrong, you should factor the x^2-9 !!

 

[Mathdabbler]

Although your last line is wrong, you should factor the x^2-9 !!

Yes - I see that now. Thanks