Answer:
[tex]=-2y^{10}[/tex]
Step-by-step explanation:
[tex]\left(y^8\right)\left(-2y^2\right)\\\mathrm{Remove\:parentheses}:\quad \left(a\right)=a\\=-y^8\cdot \:2y^2\\\mathrm{Apply\:exponent\:rule}:\quad \:a^b\cdot \:a^c=a^{b+c}\\y^8y^2=\:y^{8+2}\\=-2y^{8+2}\\\mathrm{Add\:the\:numbers:}\:8+2=10\\\ =-2y^{10}[/tex]
