I'm cubing the binomial (3x+2)^3. THe answer is 54x^2 according to my book, however I got different answers each time. Once I got 74x^2. How do I get 54x^2? I know the order of operations but when I followed it, the boo answer was not the one I got.

Question

I'm cubing the binomial (3x+2)^3.  THe answer is 54x^2 according to my book, however I got different answers each time.  Once I got 74x^2.  How do I get 54x^2? I know the order of operations but when I followed it, the boo answer was not the one I got.

bobpursley · Answer

Pascals Triangle is one way
1
11
121
1331 which means the coefficents will be
1(3x)^3 +3(3x)^2*(2)^1 + 3(3x)^1 (2)^2 +2^3

or

27x^3 + 54x^2+ 36x+ 8

The other way is to just multiply it out . I suspect you forgot the 2