afla termenul necunoscut
(20:a+20):6=50:10
8x4+9xa=86


Răspuns :

1) (20:a+20):6=50:10
(20:a+20):6=5
20:a+20=5×6
20:a+20=30
20:a=30-20
20:a=10
a=20:10
a=2


2) 8×4+9×a=86
32+9×a=86
9×a=86-32
9×a=54
a=54:9
a=6