log(32)0.25=log(2^5)2^(-2)=-2/5*log(2)2=<u>-2/5</u>
A) -4y(y+2)+(y-5)^2 =
= -4y^2-8y+y^2-10y+25 = -3y^2-18y+25
B) 2(a-3)^2-2a^2 =
=2(a^2-6a+9)-2a^2 = 2a^2-12a+18-2a^2 = -12a+18
40*35=1400 руб должен был заплатить
1400:100*5=70 руб скидка
1400-70=1330 руб заплатил
X^2 + x - 56 = 0
D = b^2 - 4ac = 1+ 224 = 225
√D = 15
x1 = (-1 + 15) /2 = 7
х2 = (-1 - 15) /2 = -16/2 = -8
Решение
<span>sin α = -4/5 и α ∈(3/2π;2π)
</span>sin²(α/2) = (1 - cosα)/2
cosα = √(1 - sin²α) = √(1 - (-4/5)²) = √9/25 = 3/5
sin²(α/2) = (1 - 3/5)/2
<span>sin²(α/2) = (2/5) : 2
</span><span>sin²(α/2) = 1/5
</span>sin(α/2) = √(1/5); sin(α/2) = √5/5
sin(α/2) = - √(1/5); <span>sin(α/2) = - </span>√5/5