NEW YORK (AP) ¿ GenCorp Inc. unit Aerojet said Monday it agreed to build a solar system with Solar Power Inc. at Aerojet's Sacramento, Calif. facility. Financial terms were undisclosed. The 3.5 megawatt solar system is the first that Aerojet has installed and is expected to offset about 4,200 tons of carbon dioxide, 16.7 tons of sulfur dioxide and about 6.5 tons of nitrogen oxide during its first year of use. Installation is expected to be complete in November. Shares of GenCorp, an aerospace supplier and manager of a real-estate portfolio, rose 2 cents to $2.18 in afternoon trading.