Răspuns:
a²+b²+c²=18²+19²+20²
=324+361+400
=1085
Explicație pas cu pas:
{a + 2; b +3; c +4} d.p. {10; 11; 12}
a+b+c=57
(a+2)/10=(b+3)/11=(c+4)/12=k
a+2=10k=> a=10k-2
b+3=11k=> b=11k-3
c+4=12k=> c=12k-4
a+b+c=10k-2+11k-3+12k-4=57
33k-9=57
33k=66
=> k=2
a=10×2-2=18
b=11×2-3=19
c=12k-4=20
a=18; b=19; c=20
a=18; b=19; c=19
a²+b²+c²=324+361+400=1085
