* Brazil Q3 GDP growth much weaker than expected * Brazilian electric utilities up on government offer * Brazil Bovespa falls 0.65 pct, Mexico IPC down 0.61 pct By Danielle Assalve SAO PAULO, Nov 30 (Reuters) - Brazilian stocks slipped on Friday after data showed Latin America's largest economy grew far slower than expected in the third quarter, suggesting growth estimates for this year and next could wilt. Latin America's major stock indexes eked out only minor gains in No