a, 35.(34+86) +65.(75+45)= 35. 120 +65.120= 120.(35+65)=120.100=12000
a, 35x34+35x86+65x75+65x45
=35x(34+86)+65x(75+45)
=35x120+65x120
=120x(35+65)
=120x100
=12000
b,3x25x8+4x6x37+2x8x12
=24x25+24x37+24x8
=24x(25+37+8)
=24x70
=1680
35 x 34 + 35 x 86 + 65 x 75 + 65 x 45
= 35 x ( 34 + 86 ) + 65 x ( 65 + 45 )
= 35 x 120 + 65 x 120
= 120 x ( 35 + 65 )
= 120 x 100 = 12000