34 nu sunt buburuze...=> f+a=34 (sunt fluturi si albine)
26 nu sunt fluturi.........=> a+b=26 (sunt albine si buburuze)
30 nu sunt albine........=> f+b=30 (sunt fluturi si buburuze)
si avem....
f+a=34
a+b=26
f+b=30
-------------
f+b+a=?
2f+2b+2a=34+26+30
2f+2b+2a=90............=>....f+b+a=90:2......=> ...f+b+a=45 insecte in total
2a+2b+2f-a+b=90-26
a+b+2f=64
26+2f=64
2f=64-26
2f=38
f=38:2
f=19 fluturi...............=>.....a+b=45-19....=>....a+b=26
2a+2b+2f-f+b=90-30
2a+b+f=60
2a+30=60
2a=60-30
2a=30
a=30:2
a=15 albine.............=>...f+b=45-15....=>f+b=30
2a+2b+2f-f+a=90-34
a+2b+f=56
2b+34=56
2b=56-34
2b=22
b=22:2
b=11 buburuze.......=>....f+a=45-11....=>...f+a=34
verificare
f+a=19+15....=>...f+a=34
f+b=19+11....=>...f+b=30
a+b=15+11...=>...a+b=26
f+b+a=45 gaze in total
19+11+15=
=30+15
=45 gaze au facut elevii in total
