2) (2/35+3/28)+2/28=
=(3/28+2/28)+2/35=
=5/28+2/35=
=25/140+8/140=33/140
4) (5/24+11/60)+(13/60+1/24)=
=(5/24+1/24)+(11/60+13/60)=
=6/24+24/60=
=1/4+2/5=5/20+8/20=13/20
...........................................................
50*5=250м
950-250=700м
50*2=100м/минут
700/100=7 минут
Начнём с последнего:
f(x) =6x² + 32x +2008
f⁾(x) = 12x +32
f⁾(x) = 0 ⇒12x + 32 = 0
12x = -32
x = -2 2/3
f(x) = 12x³ + 2x⁴
f⁾(x) = 36x² +8x³ = 4x²(9 + 2x)
f⁾(x)=0 ⇒x=0; x=-4,5
f⁾(x) <0 , x ∈(-∞; -4,5)
f(x) = x⁵ - 3x⁴+ x, x= -2
f⁾(x) = 5x⁴ - 12x³ + 1
f⁾(-2) = 5*16 -12 *(-8) +1=90+96+1=187
f(x) =x¹⁰; f⁾(x) = 10x⁹
f(x) = -6x²; f⁾(x) = -12x
f(x) = 6x⁵ - 4x⁴ - 3x +27; f⁾(x) = 30x⁴ -16x³ - 3
f(x) = (x⁴ - 3)(x³ + 4) = x⁷ -3x³ +4x⁴ -12; f⁾(x) = 7x⁶-9x² + 16x³
f(x) = (3-2x)⁷; f⁾(x) =-2*7(3-2x)⁶ = -14(3-2x)6
f(x) =sin7x; f⁾(x) = 7cos7x
f(x) = cos²x; f⁾(x) =-2cosx*sinx = -sin2x
f(x) = cosx+ sinx; f⁾(x) = -sinx+cosx
(8х/9)+1=11/3
(8х/9)=(11/3)-1
(8х/9)=8/3
24х=72
х=72/24
х=3
ответ:3