Решить уравнение: a)√x^2-3x=x+3 b)6/x + 6/x+1 =5

Question

Решить уравнение:
a)√x^2-3x=x+3
b)6/x + 6/x+1 =5

Answer 1

√x^2 - 3x = x + 3
x^2 - 3x = ( x + 3)^2
x^2 - 3x = x^2 + 6x + 9
x^2 - x^2 - 3x - 6x = 9
- 9x = 9
x = - 1

6/x + 6/x + 1 = 5
6( x + 1) + 6x = 5x(x + 1)
6x + 6 + 6x = 5x^2 + 5x
12x - 5x - 5x^2 + 6 = 0
- 5x^2 + 7x + 6 = 0
5x^2 - 7x - 6 = 0
D = b^2 - 4ac = 49 + 120 = 169 = 13^2
x1 = ( 7 + 13) / 10 = 2
x2 = ( 7 - 13) / 10 = - 0,6