Answer:
a. [tex]-3x^{5}y^{6}[/tex]
Step-by-step explanation:
We want to multiply and simplify:
[tex]-3x^2y^2\times y^4x^3[/tex]
We rearrange the product to obtain:
[tex]-3x^2\times x^3\times y^2\times y^4[/tex]
Recall that:
[tex]a^m\times a^n=a^{m+n}[/tex]
We apply this property to obtain:
[tex]-3x^{2+3}y^{2+4}[/tex]
We simplify to obtain:
[tex]-3x^{5}y^{6}[/tex]