A) |10 - 3а| = 3a - 10 ===> 10 - 3a <0, 3a > 10, a > 10/3 = = 3 1/3
б) |5 - 4a| = 5 - 4a ===> 5 - 4a >= 0, 4a <= 5, a <= 5/4 =
= 1.25
в) |18 - 9a| / (18 - 9a) = 1 ===> 18 - 9a > 0, 9a < 18
a < 18/9 = 2
г) |10a - 45| / 10a - 45 = -1 ===> 10a - 45 < 0 10a > 45
a > 45 / 10 = 4.5
Ответ. а) a > 31/3, б) a <= 1.25, в) a < 2, г) a > 4.5
X-y = 12 => y = x-12
x^2 - y^2 = 44
x^2 - (x-12)^2 = 44
x^2 - (x^2 - 24x + 144) = 44
24x - 144 = 44
24x = 188
x = 188/24 = 94/12 = 47/6
y = x - 12 = 47/6 - 12 = 47/6 - 72/6 = - 25/6
ответ: 25/6 (двадцать пять шестых)
Cos²α+cos²β+cos²γ=1
cos²γ=1-cos²α-cos²β=1-cos²120°-cos²45°=1-(1/2)²-(√2/2)²=1-1/4-1/2=1/4
cosγ₁=1/2 cosγ₂=-1/2 поскольку α=120°, т.е. координата по х<0, то
γ=-60°=300°.
A) (b+c)(a+1)
b) -3(b-c)+a(b-c)=(b-c)(a-3)