Holly finds that (11m – 13n + 6mn) – (10m – 7n + 3mn) = m – 20n + 9mn. What error did Holly make?
A She only used the additive inverse of 10m when combining like terms.
B She added the polynomials instead of subtracting.
C She only used the additive inverses of –7n and 3mn when combining like terms.
D She did not combine all like terms.

Many radioactive atoms that have large masses undergo radioactive decay by releasing a particle that is identical to a helium-4 nucleus. what changes in the original atom are expected as a result of this natural phenomenon? the atomic number and the mass number will decrease. the atomic number and the mass number will increase. the atomic number will increase, and the mass number will decrease. the atomic number will decrease, and the mass number will increase.