Find: (6m5 + 3 – m3 – 4m) – (–m5 + 2m3 – 4m + 6) Write subtraction of a polynomial expression as addition of the additive inverse. (6m5 + 3 – m3 – 4m) + (m5 – 2m3 + 4m – 6) Rewrite terms that are subtracted as addition of the opposite. 6m5 + 3 + (–m3) + (–4m) + m5 + (–2m3) + 4m + (–6) Group like terms. [6m5 + m5] + [3 + (–6)] + [(–m3) + (–2m3)] + [(–4m) + 4m] Combine like terms. Write the resulting polynomial in standard form. m5 – m3 + m – 3

Exactly right down to the last step, but some errors in combining terms.

(6m^5 + 3 – m^3 – 4m) – (–m^5 + 2m^3 – 4m + 6)
= (6m^5 + 3 – m^3 – 4m) + (m^5 – 2m^3 + 4m – 6)
= 6m^5 + 3 + (–m^3) + (–4m) + m^5 + (–2m^3) + 4m + (–6)
= [6m^5 + m^5] + [3 + (–6)] + [(–m^3) + (–2m^3)] + [(–4m) + 4m]
= (6+1)m^5 +(-1-2)m^3 +(-4+4)m +(3-6)
= 7m^5 – 3m^3 – 3