1) x=11-y
2y= -(11-y)+13
x=11-y
2y= -11+y+13
x=11-y
y=2
y=2
x=9
Решение
sin²x + sinx - 2 = 0
sinx = t, t ∈ [-1;1]
t² + t - 2 = 0
D = 1 + 4*1*2 = 9
t₁ = (- 1 - 3)/2 = - 2 ∉ [-1;1]
t₂ = (-1 + 3)/2 = 1
sinx = 1
<span> x = π/2 + 2πk, k ∈ Z</span>
Х1=4.25
х2=0.25
подучи формулу дискриминанта и х1 и х2