* Bachelet begins second term with reform agenda
* Vows to leave Chile 'a better country to live in'
* South American foreign ministers to discuss Venezuela unrest (Adds Bachelet quotes and economic context, paragraphs 4-6, details)
By Alexandra Ulmer and Anthony Esposito
VALPARAISO/SANTIAGO, March 11 (Reuters) - Michelle Bachelet took over the presidency of Chile in a ceremony loaded with symbolism on Tuesday, promising to stick to her tax-and-spend campaign pledges to fight social inequality despite a sharp economic slowdown.
Bachelet accepted the presidential sash from Senate head Isabel Allende, the daughter of late socialist President Salvador Allende, whose overthrow in 1973 ushered in the 17-year dictatorship of Augusto Pinochet.
Returning to the job she held between 2006 and 2010, Bachelet heads a coalition that ranges from moderate leftists to communists. She wants to use tax reforms to overhaul education and healthcare.
"Chile has a single enemy and that is inequality and only together can we overcome it," she said in a speech on the balcony of the presidential palace La Moneda on Tuesday evening, to cheering crowds waving Chilean flags.
"On the day I leave this house I want you all to feel that your life has changed for the better, that Chile is not just a list of indicators or statistics but a better country to live in."
Those indicators and statistics are not looking great. Economic activity growth slowed to a near four-year low in January, the peso has slid over 8 percent in the year to date and the crucial copper price is at its weakest since 2010.
Bachelet's swearing-in on Tuesday afternoon in the port city of Valparaiso, the seat of Chile's Congress, was attended by presidents from around the region, with the notable exception of Venezuela's Nicolas Maduro, who was due to come but cancelled at the last minute.
Venezuela has been rocked by civil unrest, with at least 22 deaths in five weeks of street protests demanding Maduro's resignation. A Chilean was the first foreign fatality this week.
An emergency meeting of South American foreign ministers, including Venezuela's Elias Jaua, is planned for Wednesday to discuss the unrest.
In a possible reflection of the strategic importance of Chile - a non-permanent member of the U.N. Security Council - U.S. Vice President Joe Biden was also in Santiago to attend the ceremony. He met with Bachelet and other Latin American leaders, with Venezuela high on the agenda.
Biden expressed the view that a resolution to the crisis would require third party mediation but that could not be imposed, said a U.S. administration source.
The 1973 coup and years of repression that followed it have left unresolved issues in Chile, with the 40th anniversary last year inflaming sensitivities just as the election campaign was getting started.
Salvador Allende committed suicide as air force jets strafed the La Moneda on Sept 11. 1973.
Many of his supporters fled into exile as the military cracked down on dissent, including both his daughter Isabel and a young Michelle Bachelet, who was temporarily imprisoned and tortured.
Isabel Allende (not the Chilean author, who is a distant relative) is now a Socialist Party politician and was named as the first female head of Chile's senate last month.
In that role on Tuesday she swore in Bachelet, who led Chile as its first female president in her first term. The two women smiled and embraced as Allende placed the presidential sash on Bachelet.
Barred constitutionally from immediate re-election, the popular and charismatic Bachelet easily beat her right-wing opponent when she returned to fight for the 2013 presidential vote. She is the first Chilean leader to serve a second term since the return to democracy, and will take over from unpopular conservative Sebastian Pinera.
"Pinera was not a good president, he didn't help with health or education," said civil servant Manuel Ortega near La Moneda.
"Bachelet needs to make some serious decisions in office and I hope she will put forward solutions to help the poor." (Addititional reporting by Felipe Iturrieta, Fabian Cambero and Jade Hobman, Writing by Rosalba O'Brien Editing by W Simon and Tom Brown)