Решите неравенство
f'(x)<= 0 .если f(x) =-2x^2+8x+7

f ( x ) = - 2x^2 + 8x + 7 f ' ( x ) = - 4х + 8 f ' ( x ) < = 0 - 4x + 8 < = 0 4x > = 8 x > = 2 [ 2 ; + бесконечность)