Question

Collect like terms.z3 - 3z4 + 12z2 + z4 - 10z3

Answer 1

Just gonna clarify this for dnova; he means the following:
\[z^3 - 3z^4 + 12z^2 + z^4-10z\]

Answer 2

Group all like terms together and add or subtract
12z^2+(z^3-10z^3)+(-3z^4+z^4)
=12z^2-9z^3-2z^4
Remember the exponents don't change
Sorry I thought I had made a mistake, but yeah this should be the answer.

Answer 3

And by convention, you put it in terms of decreasing degrees (decreasing exponents) :)
\[-2z^4 - 9z^3 + 12z^2\]