Răspuns:
Explicație pas cu pas:
2+5=2+(4*1+1)=7
7+9=7+(4*2+1)=16
16+13=16+(4*3+1)=29
29+17=29+(4*4+1)=46
46+21= 46+ (4*5+1)=67
67+(4*6+1)=67+25=92
92+(4*7+1)=92+29=121
121+(4*8+1)=121+33=154
