please help me out here the problem is combining like terms.

Question

4x^3-3x^3+9x+2x
I got 1x^3+11x
but when i asked a friend they said it would be x^3+11x
could u help me out please.
also could you tell me if this probem is correct as well (10x^3+6x^2+4x) -(8x^3+2x^2-3x)= 18x^3+4x^2+3x+4

Answer 1

you are both correct

1x^3+11x is the same as x^3+11x

a coefficient of 1 in front of a variable does not have to be written.
so 1a = a

as to your second question
(10x^3+6x^2+4x) -(8x^3+2x^2-3x)
= 10x^3+6x^2+4x-8x^3-2x^2+3x
= x^3 + 4x^2 + 7x

Answer 2

x^3 and 1x^3 are the same thing. The coefficient is just usually left off when it's a 1.

As for the second problem, your answer isn't quite right. Recheck your x^3 and x terms; there should also be no constant term.