ASK Computer Systems Inc has agreement to acquire NCA Corp in a cash tender offer that values the Santa Clara developer of the MaxCim manufacturing resource planning system for DEC VAX computers at $43m and has 600 users worldwide against 1,200 for ASK with the Manman system: the terms call for ASK to pay $8.50 a share for the NCA common stock outstanding, and $1,666.67 for each $1,000 face amount unit of NCA’s line of 10.25% convertible subordinated debentures; the offer will be contingent on ASK getting acceptances for 50% of the shares.