Use foil to find the product - please check my work

[pkraus]

\(\displaystyle (5y^3w^2+z)(2y^3w^2+3z)\)

Equals

\(\displaystyle 10y^6w^4+2y^3wz+15y^3w^2z+3z^2\)

It just doesn't look right any help would be appreciated.

TIA,
Paul

 

[jesusfreak3]

you thinking it doesnt look right is correct. you forgot the w^2 that would make 2w.... and 15w.... the same so you can add. the answer should look like 10y^6 w^4 +17y^3 w^2 z+3z^2

 

[mmm4444bot]

… you forgot the w^2 that would make 2w.... and 15w.... the same …

Or, said another way, "… the exponent on w in your second term should be 2 instead of 1, which makes 2y^3w^2z and 15y^3w^2z like terms …".