X^2 + 6X + 5 = 0
D = 36 - 20 = 16 ; √ 16 = 4
X1 = ( - 6 + 4 ) : 2 = - 1
X2 = ( - 6 - 4 ) : 2 = - 5
ОТВЕТ ( - 1 ) ; ( - 5 )
48- 6x-5=4-7x
48-6x-5-4+7x=0
39+x=0
X=-39
2(c + d)/(c - d)
c=3,7 и d=1 2/5 = 1,4
2·(3,7 + 1,4)/(3,7 - 1,4) = 2·5,1/2,3 = 2·51/23 = 102/23 = 4 10/23
5sim 11π/12 cos 11π/12 = 5/2 sin 11π/6=5/2 sin(12π/6-π/6)=5/2 sin (2π-π/6)=-5/2 sin π/6==5/2*1/2=-5/4=-1.25
2sinx cosx=sin2x
sin(2π-a)=-sin a
sin π/6=1/2