Решите уравнение: (7х-5)^2=7(x+1)^2

( 7x - 5)^2 = 7( x + 1)^2
49x^2 - 70x + 25 = 7(x^2 + 2x + 1)
49x^2 - 70x + 25 = 7x^2 + 14x + 7
49x^2 - 7x^2 - 70x - 14x + 25 - 7 = 0
42x^2 - 84x + 18 = 0 ( делим на 6)
7x^2 - 14x + 3 = 0
D = b^2 - 4ac = 196 - 84 = 112
x1,x2 = ( 14 +/-√112) / 14 = (14 +/- 4√7) / 14