June 10, 1982

Israel said tonight that its air force destroyed the Syrian surface-to-air missile system in the Bekaa Valley of eastern Lebanon ''in a concentrated strike'' this afternoon. Twenty-two Syrian MIG's were reported shot down in the air battle that accompanied the raid, and seven more were said to have been hit. Israel said all its planes returned safely. It did not disclose the number of planes involved. (Syria said 90 Israeli planes attacked the SAM batteries. It said 19 Israeli and 16 Syrian planes were shot down.)

The Dow Jones industrial average sank to 795.57 yesterday, piercing the 800-point mark widely regarded as a key support level. The selling pressure reflected the combined pressures of the intensifying Middle East crisis, high interest rates, the weakening economy and the continued inability of Congress to reach a compromise on the budget deficit. The blue-chip barometer, which was off almost 10 points at 3 P.M., recovered somewhat in the last hour of trading on bargain hunting. At the close it was down 6.66 points. In the last four weeks the average has tumbled 74 points.

The Mobil Corporation announced yesterday that it would end its oil exploration and production operations in Libya by July 13. Mobil, the nation's second-largest oil company, did not explain why it was withdrawing from Libya beyond saying in a prepared statement that the decision was based solely on economics. Industry analysts said that Mobil might have been under pressure from Saudi Arabia to withdraw from Libya, because the two Arab nations are at odds. Mobil is one of the four American oil companies in the Arabian American Oil Company, which produces most of Saudi Arabia' oil. Mobil becomes the second to announce its withdrawal from Libya. The Exxon Corporation said last November that it was withdrawing from the North African nation, which as recently as 1980 was the third-largest source of American oil imports. A few days after Exxon announced its plan to withdraw, Mobil said that it had halted oil production in Libya.

Graduating seniors at Medgar Evers College in Brooklyn held their own commencement last night after the college president canceled it. The ceremony combined elements of black culture and Western academic tradition. The school's 11th annual commencement for the 418 seniors was held at the Brooklyn Academy of Music by a coalition of students, faculty members and community residents. After students marched in to the auditorium to a recording of the gospel song ''Peace Be Still'' and the poetry of Nikki Giovanni, a black poet, speaker after speaker recalled the recent protest at Medgar Evers surrounding complaints about its president, Dr. Richard D. Trent. They also called on the seniors to continue to fight for equality and freedom as they entered their chosen professions.

Tens of thousands of Americans apparently are illegally avoiding taxes on dividends, interest and other sources of income by having the funds sent to foreign addresses. The practice is costing the Government hundreds of millions of dollars in uncollected taxes, Internal Revenue Service audit documents indicate. Under current Federal tax law, income on dividends, corporate bonds residential and commercial rents and royalties sent to foreign addresses is generally subject to a 30 percent tax that the paying institution must withhold. But under treaties that the United States has with 50 countries, this tax is reduced to between 15 percent and nothing for legitimate residents of those countries.