(4x^2y) ×(2x^3y^2)=(4×2)×(x^2×X^3)×(y×y^2) ( )=8x^5y^3 ( )(-2xy^2)(-xy)-(-3xy^2)^2 =2x^2y^4-9x^2y^4 ( )-7x^2y^4 ( ) 在括号内填上运算依据

问题描述:

(4x^2y) ×(2x^3y^2)
=(4×2)×(x^2×X^3)×(y×y^2) ( )
=8x^5y^3 ( )
(-2xy^2)(-xy)-(-3xy^2)^2
=2x^2y^4-9x^2y^4 ( )
-7x^2y^4 ( )
在括号内填上运算依据

答:
(4x^2y) ×(2x^3y^2)
=(4×2)×(x^2×X^3)×(y×y^2) ( 乘法结合律 )
=8x^5y^3 ( 同底数幂相乘,底数不变,指数相加 )
(-2xy^2)(-xy)-(-3xy^2)^2
=2x^2y^4-9x^2y^4 ( 同底数幂相乘,底数不变,指数相加 )
=-7x^2y^4 ( 合并同类型 )