3(y-1)^2+6y=3(y^2-2y+1)+6y=3y^2-6y+3+6=3y^2+3
12 - 3х = 4х - 8
12 + 8 = 4х + 3х
20 = 7х
х = 20 : 7
х = 2 6/7
y = x² + 3x + 2
a) x = - 2
y = (-2)² + 3 * (- 2) + 2 = 4 - 6 + 2 = 0
При x = - 2 , y = 0
б) y = 6
6 = x² + 3x + 2
x² + 3x - 4 = 0
x₁ = - 4 x₂ = 1
При x = - 4 и x = 1 , y = 6
в) y = 0
x² + 3x + 2 = 0
x₁ = - 2 x₂ = - 1
При x = - 2 и x = - 1 значения функции равны нулю .