Question

a) Tìm x,y thỏa mãn: x²-4y²=24 vào 5x+14y-2xy=35

b) CM rằng:(199³-199)\(⋮\)200

Answer 1

b: \(199^3-199\)

\(=199\left(199^2-1\right)\)

\(=199\left(199-1\right)\left(199+1\right)\)

\(=199\cdot198\cdot200⋮200\)