1) x² + 8x + 15 = 0
(x + 3)(x + 5) = 0
x + 3 = 0 atau x + 5 = 0
x = -3 atau x = -5
2) x² - 2x = 8
x² - 2x - 8 = 0
(x - 4)(x + 2) = 0
x - 4 = 0 atau x + 2 = 0
x = 4 atau x = -2
3) x² + 10 = 7x
x² - 7x + 10 = 0
(x - 2)(x -5) = 0
x - 2 = 0 atau x - 5 = 0
x = 2 atau x = 5
4) 4x² + 7x + 3 = 0
4x² + 4x + 3x + 3 = 0
4x (x + 1) + 3(x + 1) = 0
(4x + 3)(x + 1) = 0
4x + 3 = 0 atau x + 1 = 0
4x = -3 atau x = -1
x = -¾ atau x = -1
5) 4x² - 22x -12 = 0
4x² - 24x + 2x - 12 = 0
4x (x - 6) + 2(x - 6) = 0
(4x + 2) (x - 6) = 0
4x + 2 = 0 atau x - 6 = 0
x = -½ atau x = 6
6) 6x² + 8x - 8 = 0
6x² + 12x - 4x - 8 = 0
6x(x + 2) - 4(x + 2) = 0
(6x - 4)(x + 2) = 0
6x - 4 = 0 atau x + 2 = 0
6x = 4 atau x = -2
x = ⅔ atau x = -2
7) 10x² + 36x - 16 = 0
10x² + 40x - 4x - 16 = 0
10x(x + 4) - 4(x + 4) = 0
(10x - 4) (x + 4) = 0
10x - 4 = 0 atau x + 4 = 0
10x = 4 atau x = -4
x = ⅖ atau x = -4
8) 6x² - 21x + 15 = 0
6x² - 6x - 15x + 15 = 0
6x(x - 1) - 15(x - 1) = 0
(6x - 15) (x - 1) = 0
6x = 15 atau x - 1 = 0
x = 5/2 atau x = 1
9) 2x² -14x + 24 = 0
2x² - 6x - 8x + 24 = 0
2x (x - 3) - 8 (x - 3) = 0
(2x - 8)(x - 3) = 0
2x = 8 atau x - 3 = 0
x = 4 atau x = 3
10) x² + 6x + 9 = 0
(x + 3)(x + 3) = 0
(x + 3)² = 0
x = -3