Question

Решить уравнение:

2(x2 – 3) = (x – 2)(2x + 1).

Answer 1

2x^2 - 6 = 2x^2 + x - 4x - 2
2x^2 - 6 = 2x^2 - 3x - 2
- 6 = - 3x - 2
- 3x - 2 + 6 = 0 
- 3x + 4 = 0
- 3x = - 4
x = 4/3

Answer 2

2(x2-3)=(x-2)(2x+1)
4x-6=2x^2+x-4x-2
4x-6-2x^2-x+4x+2=0
7x-4-2x^2=0
D=49-32=17
$1x = \frac{ - 7 + \sqrt{17} }{4}$
$2x = \frac{ - 7 - \sqrt{17} }{4}$