Question

( 2x - 1) (2x + 1) - ( x - 3) (x+1) = 18 Помогите пожалуйста​

Answer 1

Ответ:

4x^2 - 1 - (x^2 + x - 3x - 3) - 18 = 0

4x^2 - 1 - (x^2 - 2x - 3) - 18 = 0

4x^2 - 1 - x^2 + 2x + 3 - 18 = 0

3x^2 + 2x - 16 = 0

D = 4 + 4*16*3 = 196 = 14^2

x1 = ( - 2 + 14)/6 = 12/6 = 2;

x2 = ( - 2 - 14)/6 = - 16/6 = - 8/3 = - 2 целых 2/3