х =-в /2а= 12/6=2
у=(4ас-в²)/4а=(4*3-144)/12=-11
Держи))) Очень легкие, постарайся понять
по формуле разности квадратов
![16-(a-2)^2=4^2-(a-2)^2=(4+(a-2))(4-(a-2))=(4+a-2)(4-a+2)=(2+a)(6-a)](https://tex.z-dn.net/?f=16-%28a-2%29%5E2%3D4%5E2-%28a-2%29%5E2%3D%284%2B%28a-2%29%29%284-%28a-2%29%29%3D%284%2Ba-2%29%284-a%2B2%29%3D%282%2Ba%29%286-a%29)
5tgx - 12/tgx + 11 = 0
5tg²x + 11tgx - 12 = 0 (tgx ≠ 0)
Пусть t = tgx.
5t² + 11t - 12 = 0
D = 121 + 5•12•4 = 361 = 19²
t1 = (-11 + 19)/10 = 8/10 = 4/5
t2 = (-11 - 19)/10 = -30/10 = -3
Обратная замена:
tgx = 4/5
x = arctg(4/5) + πn, n ∈ Z
tgx = -3
x = arctg(-3) + πn, n ∈ Z.