a)2la 74:(2la 3x2la 70)+103x(2+2x102)=
2la 74:2la 73+103x(2+204)=
2 la 1+103x206=
2+103x2x103=
2+2x103 la 2=
2(1+103 la2)
b)(2la 3)la3:2 la8+6 la2:(2x3 la2)=
2la9:2la 8+36:(2x9)=
2+36:18=
2+2=4
c)(1+2 la2)x(3la2:9-1):8+1987 la 0=
(1+4)x(9:9-1):8+1=
5x0+1=1
d)1la 1997+3 la0x2la 3-1997la 1998:1997la 1998=
1+1x8-1=8