11*-5-13у+16=0
-55-13y+16=0
-13y=-16-55
-13y=-71 умножаем на -1
13y=71
y=5.5
<span>3а(а-2)-(а-3)²=3а</span>²-6а-а²+6а-9=2а²-9
<span>9tg^4x=6tg^2x-1 [-3п/2;0]
</span><span>9tg^4x - 6tg^2x + 1 = 0
tg</span>²x = z
9z² - 6z + 1 = 0
<span>D = 36 - 4*9*1 = 0
z</span>₁ = 6/18
z₁ = 1/3<span>
tg</span>²x = 1/3
1) tgx = - √3
x = - π/6 + πk, k∈Z
2) tgx = 1/√3
x = π/6 + πn, n∈Z не принадлежит промежутку <span> [-3п/2;0]
</span>Ответ: x = - π/6 + πk, k∈Z