X+ 168/x=26
(х²+168-26х)/х=0
х²-26х+168=0, х≠0
Д=26²-4*168=4
х1=(26+2)/2=14
х2=(26-2)/2=12
.............................................
A=3,b=13,c=-10
D=b^2-4ac=13^2-4*3*(-10)=169+120=289
D=17^2
X1=-b+17/2a=-13+17/6=4/6=2/3
X2=-b-17/2a=-13-17/6=-30/6=-5
x2 + 12x + 33 = 0
D = b2 - 4ac
D = 144 - 132 = 12 = (2√3)^2
Sin40° - √3cos40° = 2(sin40°•1/2 - √3/2•cos40°) = 2(cos(π/3)•sin40° - sin(π/3)•cos40°) = 2(sin(40° - 60°)) = 2sin(-20°) = -2sin20°.
По формуле синуса разности аргументов:
sin(x - y) = sinxcosy - cosx•siny).