So the rule with multiplying exponents of the same base is to add the exponents together. Applying this rule here would look like this:
[tex] -8x^3y^2*2x^4y^4=(-8*2)x^{3+4}y^{2+4}=-16x^7y^6 [/tex]
In short, your simplified expression is going to be -16x^7y^6.
