a)4√5 -2√5 +7√5= 11√5 -2√5 = (11-2)*√5= 9√5
b)5√7 -9√7 +4√7= 9√7 -9√7= (9-9)√7= 0*√7=0
c)1,5√11 -14√7 +0,5√11 -6√7= (1,5+0,5) * √11 -(14+6)*√7= 2√5 -20√7= 2(√5 -10√7)
d)0,(4)= 4/9
1/3 √5 -3/4√5 +2/3 -4/9 +1/12 √5 aducem la acelasi numitor
12√5 -27√5 + 24 -16 + 3√5= 15√5 -27√5 +24-16= 3√5(5-9) + 8= 3√5 * (-4) +8=
= 4[3√5 * (-2) +2]= 4 ( -6√5 +2= -24√5 +8
