Помогите решить 4sin^2+cos^2+5sinx*cosx=0

4sin²x+cos²x+5sinx*cosx=0 |:cos²x≠04sin²x/cos²x+cos²x/cos²x+5sinx*cosx/cos²x=04tg²x+1+5tgx=0tgx=y4y²+5y+1=0a=4, b=5, c=1D=5²-4*4*1=9y₁,₂=(-b+-√D)/(2*a)y₁=(-5-3)/8, y₁=-1y₂=(-5+3)/8, y₂=-1/41. y=-1, tgx=-1, x₁=-πn, n∈Z2. y=-1/4, tgx=-1/4, x₂=-arctg(1/4)+πn, n∈Z