Question

5(3a²b-ab)-(ab²+3a²b)其中a=1/2,b=1/3

快给答案

Answer 1

解：
5(3a²b-ab)-(ab²+3a²b)
=15a²b-5ab-ab²-3a²b
=(15a²b-3a²b)-5ab-ab²
=12a²b-5ab-ab²
把a=1/2 b=1/3代入上式
=12×(1/2)²×1/3-5×1/2×1/3-1/2×(1/3)²
=1-5/6-1/18
=1/6-1/18
=3/18-1/18
=2/18
=1/9

答案：1/ 9

Answer 2

解：
5(3a²b-ab)-(ab²+3a²b)
=15a²b-5ab-ab²-3a²b
=(15a²b-3a²b)-5ab-ab²
=12a²b-5ab-ab²
把a=1/2 b=1/3代入上式
=12×(1/2)²×1/3-5×1/2×1/3-1/2×(1/3)²
=1-5/6-1/18
=1/6-1/18
=3/18-1/18
=2/18
=1/9

Answer 3

5(3a²b-ab)-(ab²+3a²b)
=15a²b-5ab-ab²-3a²b
=12a²b-5ab-ab² a=1/2,b=1/3
=1-5/6-1/18
=1-15/18-1/18
=2/18
=1/9