Respuesta :

Combine like terms (-15xz-4xy) + ((20xy-xy) - 9yz - 16xz)
Simplify to -15xz-4xy+19xy-9yz-16xz
Collect like terms
(-15xz-16xz) + (-4xy+19xy) -9yz
Your answer is -31xz+15xy-9yz
robotmasterpig
 - 31xz + 16xy - 9yz is your answer