2) 36+12у+у^2 -81=0
y^2 +12y-45=0
D=144+180=324
y1= -12-18 / 2 = -30/2 = -15
y2= -12+18 / 2 = 6/2 = 3
Ответ: -15; 3
4) 25- (169+26t+t^2)=0
25-169-26t-t^2=0
-t^2-26t-144=0
t^2+26t+144=0
D= 676-576=100
t1= -26-10 / 2 = -36/2 = -18
t2= -26+10 / 2 = -16/2 = -8
Ответ: -18; -8
X5=-1,5, x6=3/4=0,75
d=x6-x5,d=0,75-(-1,5)=0,75+1,5=2,25, d=2,25
x4=x5-d,x4=-1,5-2,25=-3,75,x4=-3,75
x7=x4+3d,x7=-3,75+3.2,25=-3,75+6,75=3, x7=3
x4+x7=-3,75+3=-0,75
![y=arcSin(Sin5)\\\\y\in[-\frac{\pi }{2};\frac{\pi }{2}]\\\\Siny=Sin(arcSin(Sin5))\\\\Siny=Sin5\\\\Siny-Sin5=0\\\\2Sin\frac{y-5}{2}Cos\frac{y+5}{2} =0\\\\1)Sin\frac{y-5}{2}=0\\\\\frac{y-5}{2}=\pi n\\\\y-5=2\pi n\\y_{1}=5+2\pi n](https://tex.z-dn.net/?f=y%3DarcSin%28Sin5%29%5C%5C%5C%5Cy%5Cin%5B-%5Cfrac%7B%5Cpi+%7D%7B2%7D%3B%5Cfrac%7B%5Cpi+%7D%7B2%7D%5D%5C%5C%5C%5CSiny%3DSin%28arcSin%28Sin5%29%29%5C%5C%5C%5CSiny%3DSin5%5C%5C%5C%5CSiny-Sin5%3D0%5C%5C%5C%5C2Sin%5Cfrac%7By-5%7D%7B2%7DCos%5Cfrac%7By%2B5%7D%7B2%7D+%3D0%5C%5C%5C%5C1%29Sin%5Cfrac%7By-5%7D%7B2%7D%3D0%5C%5C%5C%5C%5Cfrac%7By-5%7D%7B2%7D%3D%5Cpi+n%5C%5C%5C%5Cy-5%3D2%5Cpi+n%5C%5Cy_%7B1%7D%3D5%2B2%5Cpi+n)
![2)Cos\frac{y+5}{2}=0\\\\\frac{y+5}{2}=\frac{\pi }{2}+\pi n\\\\y+5=\pi + 2\pi n\\\\y_{2}=\pi -5+2\pi n](https://tex.z-dn.net/?f=2%29Cos%5Cfrac%7By%2B5%7D%7B2%7D%3D0%5C%5C%5C%5C%5Cfrac%7By%2B5%7D%7B2%7D%3D%5Cfrac%7B%5Cpi+%7D%7B2%7D%2B%5Cpi+n%5C%5C%5C%5Cy%2B5%3D%5Cpi+%2B+2%5Cpi+n%5C%5C%5C%5Cy_%7B2%7D%3D%5Cpi+-5%2B2%5Cpi+n)
y₂ - не подходит
при n = - 1
y₁ = 5 - 2π
Так как arcSin(Sin5) = y , то arcSin(Sin5) = 5 - 2π
3^-11*7^-12:21^-12= ((3*7)^-11*7^-1):21^-12=(21^-11*7^-1)/21^-12=21/7=3