Răspuns:
Explicație pas cu pas:
3) x²+x+1/x²+1/x = ? (x+1/x) = 4
x²+x+1/x²+1/x = (x²+1/x²) + (x+1/x) = (x+1/x)² - 2(x·1/x) + (x+1/x) =
= 4²-2+4 = 16+2 = 18
2)a) x:3 = a ; x:4 = b ; x: 5 = c ; x :7 = d rest 1
x = 3a ; x = 4b ; x = 5c ; x = 7d+1
240:3 = 80 rest 0 ; 240:4 = 60 rest 0 ; 240:5 = 48 rest 0 ;
240:7 = 34 rest 2 => Nu pot fi 240 fructe in cos.
b) cel mai mic numar de fructe = 120 =>
cmmdc (3,4,5) = 3·4·5 = 60
60·2 = 120 ; 120:3 = 40 ; 120:4 = 30 ; 120:5 = 24 ; 120:7 = 17 rest 1
