a) ah=5 м+hk=7 м+kd=9=21; hk=вс=7 по формуле сред.лин=вс+аd /2 ; сред.лин=21+7/2=28/2=14
,б)ah=7м+hk=9m+kd=11m=27 ;hk=вс=9 сред.лин=27+9/2=36/2=18
По теореме Виета сумма корней 6, произведение q. Из условия известно, что x1=2*x2.
x1+x2=6 <=> 3x2=6. x2=2, x1=4. q=x1*x2=8
(х+1)^2=16 х + 1 = +-4 х₁ = 4 -1 = 3 х₂ = -4 - 1 = -5
(x-1)^2=0 х - 1 =0 х = 1
(x-5)^2=1 х -5 = +-1 х ₁= 1+5 = 6 х₂ = -1 + 5 = 4
(2x-1)^2=4 2х - 1 = +-2 2х₁ = 2+1 = 3 х₁ = 3/2
2х₂ = -2 + 1 = -1 х₂ = -1/2
<span>(3x+6)^2=100 3х + 6 = +-10 3х</span>₁ = 10 - 6 = 4 х₁ = 4/3
3х₂ = -10-6 = -16 х₂ = -16/3
(3-2x)^2=25 3 - 2х = +-5 2х₁ = 3 - 5 = -2 х₁ = -2/2 = -1
2х₂ = 3 + 5 = 8 х₂ = 8/2 = 4
7х-21-10у=4у-35
6х=5у-40+56
7х=14у-14
6х=5у+16
х=2у-2
6(2у-2)=5у+16
х=2у-2
12у-12=5у+16
х=2у-2 х=2у-2 х=2*4-2 х=6.
7у=28 у=4 у=4 <span> у=4.</span>
Cos**2 a=1-sin**2a=1- 0,64=0,36
cos a =-0,6