Răspuns :
= (9x^2+ 24xy +16t^2 )+ (9y^2-24xy+16x^2)= (9+16)(x^2+y^2)
= 25x^2 + 25y^25= 25(x^2+ y^2)
= 25^2+25y^2= 25x^2+25y^2. ###
= 25x^2 + 25y^25= 25(x^2+ y^2)
= 25^2+25y^2= 25x^2+25y^2. ###