Correct order of terms

[Rich16]

Hi,

My textbook has two problems. First:
-6(x+7)+x(9x+10)-(4-x)

I've simplified to: -6x-42+9x^2+10x-4x
Then collected like terms: 5x-46+9x^2
The answer in the textbook changes the order to: 9x^2+5x-46

Second:

2(1-3x)-4(x+2)
Which would become: 2-6x-4x-8
The answer for this in the book is:
-6-10x

They haven't changed the order here. I know the result will be the same either way, but isn't the convention to have terms with the highest exponents at the start, then constants (eg. x^3+x^2+x+1)? So shouldn't it be -10x-6 (since ^1 next to -10x is implied? I just want to make sure I'm writing it conventionally even when it doesn't affect the result.

 

[HallsofIvy]

No, there is no such "convention". It is often done that way but there is no requirement.

 

[Steven G]

Hi,

My textbook has two problems. First:
-6(x+7)+x(9x+10)-(4-x)

I've simplified to: -6x-42+9x^2+10x-4x

It should be -6x-42+9x^2+10x -4 +x

 

[Maxp070704]

2(1-3x)-4(x+2)
Which would become: 2-6x-4x-8
The answer for this in the book is:
-6-10x

Yes, the book is correct, all you got to do is combine the "2" and the "-8" to get -6, and -6x and -4x to get -10x so the results is -6-10x