Răspunsuri

2014-11-10T22:10:45+02:00
1)
x+y=1 ⇒ y=1-x
(x+y)(x-y)+2y= x²-y²+2y⇒ x²- (1-x)²+2(1-x)= x²-1²+2x-x²+2-2x= -1+2=1

2) L²=aria patrat
(√2+1)²= 2+2√2 +1= 3+2√2 cm²