Question

(x-y)² , unde x²-y² =20 si x+y =5

Answer 1

x²-y²=(x+y)(x-y)⇒20=5(x-y)⇒x-y=20/5⇒x-y=4

(x-y)²=4²=16

Answer 2

 x²-y² =20<=>(x-y)(x+y)=20 (1)
 x+y =5 (2)
(2)->(1)=> (x-y)*5=20
(x-y)=4|² (ridicam toata ecuati la ²)

(x-y)²=4²=>(x-y)²=16