Question

Va rog , am nevoie , dau coroana .

Answer 1

a) E(x) = (x+1)^2+2(x+1)(x-2)+(x-2)^2
=x^2+2x+1+2x^2-2x-4+x^2-4x+4
=4x^2-4x+1
=(2x-1)^2

b) a apartine N
a=? astfel incat E(rad2) +a radica din 2 apartine N
E(rad2)= (2rad2-1)^2 = (2rad2)^2-4rad2+1=9 -4 rad2
E(rad2)+ a radical din 2=9 - 4rad2 + a raduc din 2 = 9- rad2(4-a)
9-rad2(4-a) apartine N
a apartine N => 4-a apartine Z =>4-a= 0 <=> a=4 apartine N