Răspuns :
(245:5+5×X):9+89=100
(49+5×X):9=100-89=11
(49+5×X)=11×9
49+5×X=99
5×X=99-49
5×X=50
X=50:5
X=10
(49+5×X):9=100-89=11
(49+5×X)=11×9
49+5×X=99
5×X=99-49
5×X=50
X=50:5
X=10
(245:5+5x):9+89=100
(245:5+5x):9=100-89=11
245:5+5x=11•9=99
49+5x=99
5x=99-49
5x=50
x=50:5
x=10