Expanding and moving 111 to the left gives 16c6−20c4+6c2=016c^6-20c^4+6c^2=016c6−20c4+6c2=0. Factoring yields 2c2(4c2−3)(2c2−1)=02c^2(4c^2-3)(2c^2-1)=02c2(4c2−3)(2c2−1)=0.