10(1-z)^2+20z упростите выражение

Question

10(1-z)^2+20z упростите выражение

Answer 1

(1-z)(1-z)=1-z-z+z^2=10(1-2x+z^2)+20z=10-20z+10z^2+20z=10-10z^2=10(1-z)^2