Like Terms

The governing concept is combining like terms. Terms can be added or subtracted directly only when their variable parts are identical. Group the p-terms and q-terms: (6p + 2p) + (−4q + 9q). Add their numerical coefficients separately: 6 + 2 = 8, while −4 + 9 = 5. The simplified expression is therefore 8p + 5q, so option A is correct. Option B treats the q-coefficients as though both should be subtracted. Option C incorrectly uses 6 − 2 for the p-terms. Option D multiplies p and q, even though the original operation is addition and the terms are not being multiplied. No further combination is possible because p and q are different variables.