1)(x^2 - 1) = (14 - x^2)
x^2 - 2x + 1 = 196 - 28x + x^2
x^2 - x^2 - 2x + 28x - 196 +1=0
26x = 195
x = 7,5
2) 5x - 4 = 4 - 3(5 - 2x)
5x - 4 = 4 - 15 + 6x
5x - 6x - 4 - 4 + 15 = 0
-x + 7 = 0
-x = -7
x = 7
3) -5x = 5x - 6
-5x - 5x = -6
-10x = -6
x = 0,6