What was going on when I was born?

The Reagan Administration may seek early, bipartisan help from Congress to shape a simpler tax code, an official said today. Seeking compromise with Democrats early in a Congressional session rather than later would be unusual for a President newly installed with a historic re-election margin. But an Administration official said today that the strategy was being looked at because proposals for a flat tax are already drawing interest in Congress. The Republicans did not win control of the House and Republican control in the Senate was eroded; maintaining it appears to politicians to require moves for moderation.

The F.B.I. says it has evidence linking five people arrested this week in connection with the slaying of a New Jersey state trooper to 10 bombings in the New York metropolitan area. According to testimony in Federal court here, the F.B.I. found handwritten descriptions of two corporate office buildings bombed in the New York City area this year in searches of the rented homes of the suspects, who were arrested Sunday in the Cleveland area. A group called the United Freedom Front took responsibility for the bombings, as well as for eight others in the area since December 1982. The F.B.I. also said it had found a timing device similar to one on an unexploded bomb planted at a third company, and copies of United Freedom Front communiques identical to those distributed after six of the bombings.

EVERYTHING seems to be working out right for Carter Brey, the 30-year-old cellist who will play Dvorak's beloved concerto with the American Symphony Orchestra on Sunday. He has racked up impressive competition victories, made debuts with several major orchestras, garnered rave reviews wherever he has played, won the enthusiastic support of Rostropovich and, most recently, bought a cello. Only just now? ''Believe it or not,'' Mr. Brey said the other day, ''I played every one of my public appearances until this July on a $750 Czechoslovak cello that my parents bought with a savings bond when I was 17. It was sort of infamous in the instrumental world: 'Brey's Box.' People were nice about it, but they couldn't quite believe I played it.

Twenty-six young people from abroad whose families have been wrenched apart by war arrived in New York City this week to begin telling America's children of life growing up in the shadow of destruction. Their hope, they say, is that by telling their stories to Americans they will meet in visits to 36 cities over the next 12 days, they may diminish the threat of war. ''It seems almost unbelievable that I could forgive and forget about what happened to my people,'' said Arn Chorn, an 18-year-old refugee from Cambodia, who now lives in New Hampshire with foster parents. He is an advisor to the young people on the tour, who are 14 to 17 years old. ''Children have an ability to forgive and forget.''

Education Secretary T .H. Bell announced today that he was resigning from President Reagan's Cabinet, saying he had witnessed the start of ''a real renaissance of American education.'' Mr. Bell delivered a ringing reaffirmation of the Federal role in education and candidly acknowledged having disagreed with David A. Stockman, director of the Office of Management and Budget, over the proper level of Federal spending for education. Mr. Bell also lamented the fact that he was still a target of criticism by conservative Republicans who wanted to reduce Federal aid to education. Education Gets Top Priority ''To move in the radical direction of abolishing all of our programs and dramatically withdrawing all Federal concern and support of education would be a mistake,'' Mr. Bell said at a news conference. ''I think education is so special that it ranks in priority alongside and possibly ahead of the Department of Defense. But I have to acknowledge, when I say that, it's a biased view.''

THIS weekend you can see Impressionist and modern art works by a veritable who's who of painters and sculptors of the last century as the city's two top auction houses prepare for the season's biggest week of art auctions. The works, ranging from Corot to Picasso, from Renoir to Leger, are valued at more than $60 million. In their role of ''museum-galleries'' over the weekend, the two houses, Sotheby's and Christie's, will be giving the public perhaps its only chance to see these works before many are purchased by private collectors. Among the dozens of works up for bidding next Monday and Tuesday at Christie's are two major 1920's Picasso paintings of seated women - one that hung in the Tate Gallery in London for 26 years and the other from the Walter Annenberg collection. Coincidentally, a seated woman by Corot, described by David Nash, director of fine arts at Sotheby's, as ''the most important work by the artist to appear at auction in a generation,'' will be sold by Sotheby's next Wednesday.

An audit by the City University of New York has found that almost a third of a sample of students receiving Federal aid at Medgar Evers College in Brooklyn are ineligible. At Evers, a two-year school that charges $1,225 a year in tuition, 950 of its 2,500 students receive Federal aid, with the average grant being about $1,000. The audit sampled 150 students, and a spokesman for the university system said yesterday that the records of all 950 would be reviewed. He said that an investigation was under way to determine how the improper awards were made and that students ineligible for the aid would be asked to return the money.

The Soviet Union has told the United States that it has not shipped any advanced fighter planes to Nicaragua, Secretary of State George P. Shultz indicated today. At the same time, Mr. Shultz, in an interview devoted largely to the Reagan Administration's plans for dealing with the Soviet Union in the second Reagan term, said he planned to be directly involved with Foreign Minister Andrei A. Gromyko in managing Soviet-American relations. He said he opposed the idea of naming a special ''czar'' to negotiate future arms-control accords. Such an idea has been discussed by some White House officials.

Federal bank regulators have classified some loans to Argentina as ''substandard,'' a step that might increase bank resistance to granting fresh credits and delay final approval of an International Monetary Fund program of emergency financial aid, Federal officials reported today. Last Sept. 25, Argentina and the I.M.F. announced agreement on an austerity program that was to lead to $1.4 billion of monetary fund credits over 15 months. But the action was conditional on a flow of fresh money into Argentina from the commercial banks and a stretch-out of nearly half of its foreign debt. According to New York banking sources, Argentina initially asked for $5.5 billion from the banks. The banks were offering $2.5 billion. The banks are hoping to encourage Argentina to get more money from the public sector, for example from such export credit agencies as the Export-Import Bank of the United States.

After two days of tempestuous activity, with sharply falling prices and rising bond yields, Treasury note and bond prices turned up late yesterday after the Federal Reserve announced a $600 million decline in the nation's basic money supply. Although there is no evidence yet that Fed officials decided to ease monetary policy at this week's meeting of the Federal Open Market Committee, the money supply decline served to remind credit market participants of predictions that an easing in policy is imminent. While note and bond prices ended the day unchanged, or modestly lower, they were well above the lowest levels set at midday. 'Portends a Weak Economy' ''The recent weakness of money supply growth portends a weak economy six months down the road,'' said Mickey D. Levy, chief economist at Fidelity Bank, Philadlephia. He said that ''with inflation so low, I don't see any reason why the Fed should not ease'' enough to foster lower interest rates, ''particularly since the economic data is on the weak side.'' Mr. Levy added that the overnight rate for bank loans in the Federal funds market might average around 9 1/2 percent, or slightly lower, in the near future.

The city's Board of Estimate early this morning unanimously approved a nearly $2 billion plan to rebuild Times Square. The vote, which was the final governmental authorization needed for the project, came at 1:20 A.M. after nearly a full day of negotiations in several City Hall offices over changes in the plan and after four hours of hearings in which speakers once again differed sharply over the plan's merits. The project calls for widespread demolition in an often tawdry 13-acre area centered on the block of 42d Street between Seventh and Eighth Avenues, rehabilitation of nine theaters and the Times Square subway station, and construction of a 2.4 million square foot wholesale merchandise mart, a hotel, and four office buildings, the biggest of which would be twice the bulk of the largest normally allowed under city zoning. Board of Estimate approval allows the city and state to sign 99-year leases with four sets of developers selected to build the project and to undertake condemnation proceedings, which are not expected to begin until early next year.

The still anonymous mother of Baby Fae, the infant who received the heart of a baboon, expressed some of the pressure she and her husband have been feeling in a statement released at a news conference today. ''We need peace of mind for a while,'' she said in the statement read by a spokesman at the Loma Linda University Medical Center. ''Please let us enjoy our precious child.'' She also reaffirmed an earlier expression of confidence in the operation. ''We feel we have done right for her,'' she said.