Решить (2x+3)^2=(x+4)^2

(2x + 3)^2 - (x  + 4)^2 = 0 
(2x + 3 - (x + 4)) (2x + 3 + x + 4) = 0
(2x + 3  - x - 4)(2x + 3 + x + 4) = 0 
(x - 1)(3x + 7) = 0 

1) x - 1 = 0 
x =  1;

2) 3x + 7 = 0 
3x = - 7
x = - 7/3