Răspuns :
3x(1+2x4)+1=3x9+1=28:
3x(1+2)x4+1=3x3x4+1=9x4+1=37
(3x1+2)x4+1=(3+2)x4+1=5x4+1=21
3x(1+2x4+1)=3x(1+8+1)=3x10=30
3x(1+2)x4+1=3x3x4+1=9x4+1=37
(3x1+2)x4+1=(3+2)x4+1=5x4+1=21
3x(1+2x4+1)=3x(1+8+1)=3x10=30