546+127-96/3+74x2-(62/a+24/2)-511=689 conditie a diferit de 0
546+127-32+74x2-(62/a+12)-511=689
546+127-32+148-(62/a+12)-511=689
673-32+148-(62/a+12)-511=689
641+148-(62/a+12)-511=689
789-(62/a+12)-511=689
789-(62/a+12)=689+511
789-(62/a+12)=1200
62/a+12=789-1200
62/a+12=-411
62/a=-411-12
62/a=-423
a=-62/423