Answer:
[tex]\mathrm{32x^4y^2z^{10}}[/tex]
Step-by-step explanation:
[tex]\mathrm{\left(4xyz\right)\left(8x^3yz^9\right)}\\\\\mathrm{=4yz\cdot \:8x^{1+3}yz^9}\\\\\mathrm{=4yz\cdot \:8x^4yz^9}\\\\\mathrm{=4z\cdot \:8x^4y^{1+1}z^9}\\\\\mathrm{=4z\cdot \:8x^4y^2z^9}\\\\\mathrm{=4\cdot \:8x^4y^2z^{1+9}}\\\\\mathrm{=4\cdot \:8x^4y^2z^{10}}\\\\\mathrm{=32x^4y^2z^{10}}[/tex]