Question

X 9. Scrie unul din factori ca un produs de doi sau trei factori, apoi aplică relaţia a xbxe -a*(b c), după model: Model: 15 * 6 - (3 * 5) * 6 = 3 (5 * 6) = 3 x 30 = 90. Calculeaza: 75 x 6; 25 * 8; 45 * 4; 36 * 5; 315 * 8; 485 * 4; 160 x 5. X x​

Answer 1

Explicație pas cu pas:

75 × 6 = (3 × 5 × 5) × 6 = 3 × (5 × 5 × 6) = 3 × (25 × 6) = 3 × 150 = 450

25 × 8 = (5 × 5) × 8 = 5 × (5 × 8) = 5 × 40 = 200

45 × 4 = (3 × 3 × 5) × 4 = 3 × (3 × 5 × 4) = 3 × (15 × 4) = 3 × 60 = 180

36 × 5 = (3 × 2 × 6) × 5 = 3 × (2 × 6 × 5) = 3 × (12 × 5) = 3 × 60 = 180

315 × 8 = (15 × 3 × 7) × 8 = 15 × (3 × 7 × 8) = 15 × (21 × 8) = 15 × 168 = (5 × 3) × 168 = 5 × (3 × 168) = 5 × 504 = 2 520

485 × 4 = (97 × 5) × 4 = 97 × (5 × 4) = 97 × 20 = 1 940

160 × 5 = (80 × 2) × 5 = 80 × (2 × 5) = 80 × 10 = 800