$36x^2 - (3x - 27)^2 = 0$
(6x − 3x + 27)(6x + 3x − 27) = 0
(3x + 27)(9x − 27) = 0
3x + 27 = 0
3x = −27
x = −27 : 3
$x_1 = -9$;
9x − 27 = 0
9x = 27
x = 27 : 9
$x_2 = 3$.

$(4x - 7)^2 - (2x + 17)^2 = 0$
(4x − 7 − 2x − 17)(4x − 7 + 2x + 17) = 0
(2x − 24)(6x + 10) = 0
2x − 24 = 0
2x = 24
x = 24 : 2
$x_1 = 12$;
6x + 10 = 0
6x = −10
$x_2 = -\frac{10}{6} = -\frac{5}{3} = -1\frac{2}{3}$.