3tg²x+1/tg²x=4
tg²x=y;3y+1/y-4=0
3y²-4y+1=0;y₁=1;y₂=⅓
1) tg²x=1;tgx=±1;x=±π/4+πn,n∈Z
2) tg²x=⅓;tgx=±1/√3;x=±π/6+πk,k∈Z.
<span> 4х-3(х-7)=2х+15</span>
<span>4х-3х+21=2х+15</span>
<span>-Х=15-21</span>
<span>х=6</span>
Общий знаменатель 18
2X / 18 + 9X / 18 = 33 / 18
11X = 33
X = 33 : 11
X = 3
305^2= (300 + 5)^2 = 300^2 + 2 x 200 x 5 + 5^2 = 90000 + 2000 + 25 = 92025
(х+2+7)(х+2-7)=0
(х+9)(х-5)=0
ответ: х1=-9; х2=5