Hey there!
ORIGINAL EQUATION:
1/3(12x + 6x - 21)
COMBINE the LIKE TERMS
= 1/3(18x - 21)
DISTRIBUTE 1/3 WITHIN the PARENTHESES:
= 1/3(18x) + 1/3(-21)
SIMPLIFY:
= 6x - 7
Therefore, the answer should be:
6x - 7
Good luck on your assignment & enjoy your day!
~Amphitrite1040:)