Saying the city is “lucky to have her,” Mayor Rahm Emanuel threw his full support Monday behind Deborah Quazzo, his school board appointee who sees no conflict of interest with her investments in companies that sell millions of dollars of educational software to the district she’s tasked with overseeing.

But speaking for the first time since the Chicago Sun-Times revealed that CPS’ business with companies Quazzo invested in tripled since Emanuel appointed her, the mayor refused to answer questions about when he learned about her business interests with Chicago Public Schools.

“Deb has the public spiritedness and the commitment on education as well as public policy, but on education specifically, to serve and bring that energy and that passion to her role on the CPS board,” he said at a news conference on his first day back from a South American vacation.

“Deb says she’ll answer any questions, the [Inspector General’s] going to look into it. I’m pleased that she’s volunteered her time to serve and she’s going to continue to do it,” Emanuel said of Quazzo, who donated $5,000 to his 2011 mayoral campaign.

He left as a reporter asked why he didn’t see any conflict of interest.

Quazzo, a millionaire venture capitalist, has invested in five educational technology companies that have been paid about $3.8 million by CPS since 2010, $2.9 million of it since June 2013, when she was chosen to replace Penny Pritzker, who left to become U.S. commerce secretary.

Quazzo has said she hasn’t tried to hide her involvement and sees no conflict of interest because she has recused herself from any votes before the board. She has continued to invest, saying, “It’s my belief I need to invest in companies and philanthropic organizations who improve outcomes for children.”

Several times since Quazzo took office, one of her companies cut prices so its bills to CPS fell just below the $25,000 threshold that would require approval by CPS officials.

Academic Approach, which offers ACT test-preparation help, gave Corliss High School a 2.21 percent discount on $25,565 worth of services, cutting its bill to $24,999 — $1 shy of needing central office approval. The company also sent bills just under $25,000 to three other CPS schools.

In the wake of the Sun-Times story, CPS’ inspector general opened an investigation.

Two mayoral contenders as well as the Chicago Teachers Union have called for Quazzo to resign, holding up her case as justification for an elected school board for the cash-starved district.

Last month, at a summit with U.S. Secretary of Education Arne Duncan and the mayor of Atlanta, Emanuel opposed elected school boards because they disperse accountability.

“If you don’t have control, you’re responsible with no accountability and ability to make change,” he said. “I think what the kids need is adults who are responsible and who are held accountable.”