Question

B=2+4+6+....+800 va rog ajutati-ma la acest ex

Answer 1

B=2×1+2×2+2×3+...+2×400
B=2(1+2+3+...+400)
B=2(400×401:2)
B=400×401

$\boxed{B=160.400}$

Answer 2

B=2+4+6+...+800
B=2(1+2+3+..+400)
B=2(400*401/2)
B=400*401
B=160400