(х+2у)^2-(x-2y)^2=8xy докажите торжество

Question

(х+2у)^2-(x-2y)^2=8xy докажите торжество

Answer 1

(х+2у)^2-(x-2y)^2=8xy

x^2+4xy+y^2-(x^2-4xy+y^2)=8xy 

x^2+4xy+y^2-x^2+4xy-y^2=8xy

4xy+4xy=8xy

8xy=8xy

 ДОКАЗАНО