1) { x – y = 5 xy = 6 } 2) { x2 – y2 = 21 x2 + y2 = 29 } 3) 6x+1 + 35 · 6x–1 = 41 4) 4x – 3x–0.5 = 3x+0.5 – 22x–1 5) K1 · at1+t2 + K2 · at2+t2 + K3 = 0 6) Lg Lg (2x2 – 4x + 12) = Lg Lg x + Lg Lg (x + 3)