For this case we must find the product of the following expression:
[tex](-3x ^ 5y ^ 2) * (9x ^ 3y ^ 8)[/tex]
Then, by definition of powers of the same base we have to put the same base and add the exponents:
[tex](-3 * 9) x^{5 + 3} (1 * 1)y^{8 + 2} =[/tex]
[tex]-27x ^ 8*1y ^ {10}[/tex]
ANswer:
[tex]-27x ^ 8y ^ {10}[/tex]