Question

from the sum of 2y^2+3yz,-y^2-yz-z^2 and yz+2z^2 subtract the sum of 3y^2-z^2 and -y^2+yz+z^2

Answer 1

Sum 1: 2y^2+3yz+(-y^2-yz-z^2)=3y^2+2yz-z^2

Sum 2: 3y^2-z^2+(-y^2+yz+z^2)=2y^2+yz

Difference between sums: 3y^2+2yz-z^2-(2y^2+yz)=3y^2+2yz-z^2-2y^2-yz

=y^2+yz-z^2