Question

​_____ was the first commercially successful computer. ​z3 ​eniac ​univac ​colossus

Answer 1

 ​ENIAC was the first commercially successful computer, released in 1946.
The name ENIAC Electronic Numerical Integrator And Computer).
 It was used to calculate artillery firing tables for the United States Army's Research Laboratory.
It was invented by J. Presper Eckert and John Mauchly at the University of Pennsylvania.