8sin²x+sinxcosx+cos²x-4sin²x-4cos²x=0
4sin²x+sinxcosx-3cos²x=0/cos²x
4tg²x+tgx-3=0
tgx=a
4a²+a-3=0
D=1+48=49
a1=(-1-7)/8=-1⇒tgx=-1⇒x=-π/4+πn
a2=(-1+7)/8=3/4⇒tgx=0,75⇒x=arctg0,75+πk,k∈z
3х² + 5х - 2 = 0
D = 5² - 4 · 3 · (-2) = 25 + 24 = 49; √49 = 7
x₁ = (-5 - 7)/(2 · 3) = -12/6 = -2
x₂ = (-5 + 7)/(2 · 3) = 2/6 = 1/3
<span>(-2,3+9,3)/-0,5=7/-0,5=-14</span>
А/4х = 7/(х²-10х)
а(х² -10х) = 28х
ах² -10 ах -28 х =0
ах² -(10 а + 28) х = 0
х(ах -10а -28) = 0
х = 0 или ах -10 а -28 = 0
(а-10)х = 28
х = 28/(а-10)
28/(а -10) <0 ⇒ a -10 > 0 ⇒ <em>a > 10 </em>