43x (85-81) + 85x(81-43)
= 43 x 85 - 43 x 81 + 85 x 81 - 85x 43
= 43 x 85 - 85 x 43 + 85x 81 - 43x 81
= 0 + 81 x ( 85 - 43 )
= 0 + 3402
= 3402
43x(85-81)+85x(81-43)=43x85-43x81+85x81-85x43
=(43x85-85x43)+(85x81-43x81)
=0+81x(85-43)
=81x42
=3402
43 x (85 - 81) + 85 x (81 - 43)
= 43 x 85 - 43 x 81 + 85 x 81 - 85 x 43
= 43 x 85 - 85 x 43 + 85 x 81 - 43 x 81
= 0 + 81 x (85 - 43)
= 0 + 3402
= 3402
Nhớ nha!