Răspuns:
7+ 3 - [2 +5. 4. (3 + 2x)] = 313;
7+3-60+40x=313
40x=363
x=363/40=9,075
2+20(3+2x)=313
2+60+40x=313
62+40x=313
40x=313-62
40x= 251
x=251:40
x= 6,27
