(x+1)(x-2) = x-4
x² - 2x + x - 2 = x-4
x² - x - 2 - x + 4 = 0
x² - 2x + 2 = 0
D = b² - 4ac = 4 - 8 = -4
∅
(4x-3)(4-x) = 3
16x - 4x² - 12 + 3x = 3
- 4x² + 19x - 15 = 0
4x² - 19x + 15 = 0
a + c = -19
x_1 = 1
x_2 = 15/4
(x+4)² = 3x + 10
x² + 8x + 16 = 3x + 10
x² + 5x + 6 = 0
D = b² - 4ac = 25 - 24 = 1
x_1 = (-5 + 1)/2 = -2
x_2 = (-5-1)/2 = -3
4(3+y)(3y-1) = (4-5y)y
(12 + 4y)(3y-1) = 36y - 12 + 12y² - 4y = 12y² + 32y - 12
12y² + 32y - 12 = 4y - 5y²
17y² + 28y - 12 = 0
k = b/2 = 28/2 = 14
D = k² - ac = 196 - (-204) = 400
x_1 = (-14 + 20)/17 = 6/17
x_2 = (-14 - 20)/17 = -34/17 = -2
(2x - 3)² = 11x - 19
4x² - 12x + 9 = 11x - 19
4x² - 23x + 28 = 0
D = 23² - 4•4•28 = 529 - 448 = 81
x_1 = (23+9)/8 = 4
x_2 = (23-9)/8 = 14/8 = 7/4