16) Answer: [tex]11x^6y^5[/tex]
[tex]\left(2x^5y^2\right)\left(4xy^3\right)+\left(x^4y^4\right)\left(3x^2y\right)[/tex]
[tex]=2x^5y^2\cdot \:4xy^3+x^4y^4\cdot \:3x^2y[/tex]
[tex]=8x^6y^5+3x^6y^5[/tex]
[tex]=11x^6y^5[/tex]
17) Answer: [tex]18a^4b^6[/tex]
[tex]\left(4a^3b^4\right)\left(5ab^2\right)+\left(a^2b^5\right)\left(-2a^2b\right)[/tex]
[tex]=4a^3b^4\cdot \:5ab^2-a^2b^5\cdot \:2a^2b[/tex]
[tex]=20a^4b^6-2a^4b^6[/tex]
[tex]=18a^4b^6[/tex]
