СРОЧНО,ПОМОГИТЕ РЕШИТЬ!sin2x=3/43cosX+5sinX/2+1=0

Sin2x=3/4
a)  sin2x = -3/2
2x = (-1)^n*arcsin(-3/2) + n, nZ
2x = (-1)^(n+1)*arcsin(3/2) + n, nZ
2x = (-1)^(n+1)*(/3) + n, nZ
x1 = (-1)^(n+1)*(/6) + (n)/2, nZ
b)  sin2x = 3/2
2x = (-1)^(n)*arcsin(3/2) + k, nZ
2x = (-1)^(n)*(/3) + k, kZ
x2 = (-1)(n)*(/6)  + (k)/2, kZ

2) 3cosX + 5sin X/2 + 1 = 0
3*(1 - 2sin^2(x/2) + 5sin(x/2) + 1 = 0
 6sin^(x/2) - 5sin(x/2) - 4 = 0
D = 25 + 4*6*4 = 121
a) sin(x/2) = (5 - 11)/12
sin(x/2) = (-1/2)
x/2 =(-1)^(n)* arcsin(-1/2) + n, nz
x/2 = (-1)^(n+1)*(/6) + n, nZ
x1 = (-1)^(n+1)*(/3) + n, nz
b)  sin(x/2) = (5 + 11)/12
sin(x/2) = 1
x/2 = /2 + 2k, kZ
x2 = + 4k, kz