1..(6×10^8)(7×10^9)(4×10^4) =(6*7*4)*10^21=1.68*10^23
2..(-3ab)(-a^2c)×6ab^2 =18a^4b^3c
3..(-3xy)×5x^2y+6x^2(7/2xy^2-2y^2)
=-15x^3y^2+21x^3y^2-12x^2y^2
=6x^3y^2-12x^2y^2
4..(-ab)^3×(-a^2b)(-a^2b^4c)^2
=a^5b^4*(a^4b^8c^2)=a^9b^12c^2
很高兴为你解决问题!
1..(6×10^8)(7×10^9)(4×10^4) =(6*7*4)*10^21=1.68*10^23
2..(-3ab)(-a^2c)×6ab^2 =18a^4b^3c
3..(-3xy)×5x^2y+6x^2(7/2xy^2-2y^2)
=-15x^3y^2+21x^3y^2-12x^2y^2
=6x^3y^2-12x^2y^2
4..(-ab)^3×(-a^2b)(-a^2b^4c)^2
=a^5b^4*(a^4b^8c^2)=a^9b^12c^2
很高兴为你解决问题!