Докажите неравенства: 2(4x - 1) + x < 3(3x + 2) и (y - 1)(y + 1) > y^2 - 2

Question

Докажите неравенства: 2(4x - 1) + x < 3(3x + 2) и (y - 1)(y + 1) > y^2 - 2

Answer 1

2(4x - 1) + x < 3(3x + 2) <=> 8x - 2 + x < 9x + 6 <=> -2 < 6 (верно)

(y - 1)(y + 1) > y^2 - 2 <=> y^2 - 1 > y^2 - 2 <=> -1 > -2  (верно)