12-12+8x=15+3x
8x-3x=15
5x=15
x=15/5
x=3
4xy(2x+0,5y-xy) = 8х²у + 2ху² - 4х² у²
81x²<16
x²<16/81
|x|<4/9
x∈(-4/9; 4/9)
Ответ: 4
802.
y=x³ -1
-3≤x≤2
x=-3 y=(-3)³-1= -27-1= -28
x= -2 y=(-2)³-1= -8-1= -9
x= -1 y= (-1)³-1= -2
x=0 y= 0³ -1= -1
x=1 y= 1³ -1 = 0
x=2 y=2³ -1 =8-1=7
<u>x| -3 | -2 | -1 | 0 | 1 | 2</u>
y| -28| -9 | -2 | -1 | 0 | 7
Sin20*sin40*sin80=sin20*sin(2*20)*sin(2*40)
sin20*2sin20*cos20*2sin40*cos40