Answer:
[tex]40x^{2} y^{4} -70x^{2} y^{2} +90xy^{3}[/tex]
Step-by-step explanation:
[tex]10xy(4xy^{3} -7xy+9y^2)[/tex]
1. 10xy · 4xy^3 = [tex]40x^2y^4[/tex]
2. 10xy · -7xy = [tex]-70x^{2} y^{2}[/tex]
3. 10xy · 9y^2 = [tex]90xy^3[/tex]
Final step: add up all of those values together to make an equation!
Answer: [tex]40x^2y^4+[/tex] [tex]-70x^2y^2+[/tex] [tex]90xy^3[/tex]
Final Answer: [tex]40x^2y^4-70x^2y^2+90xy^3[/tex]