a, 35.(34+86) + 65.(75+45)
=35.120 + 65.120
=120.(35+65)
=120. 100
=12000
a) 35 * 34 + 35 * 86 + 65 * 75 + 65 * 45
= 35 x ( 34 + 86 ) x 65 x ( 75 + 45 )
= 35 x 120 x 65 x 120
= 120 x ( 35 + 65 )
= 120 x 100
= 12000
b, 24.25+24.37+24.38
=24(25+37+38)
=24.100
=2400