(c+20d)²-(20c+d)²=(c+20d-20c-d)(c+20d+20c+d)=(19d-19c)(21d+21c)=
19*21*(d-c)(d+c)=399(d²-c²)
Copyright © 2024 SCHOLAR.TIPS - All rights reserved.
Answers & Comments
(c+20d)²-(20c+d)²=(c+20d-20c-d)(c+20d+20c+d)=(19d-19c)(21d+21c)=
19*21*(d-c)(d+c)=399(d²-c²)