1) 4x^2 - 4x + 1 - x^2 - 6x - 9= 0
3x^2 - 10x - 8 = 0
D = b^2 - 4ac = 100 + 96 = 196 = 14^2
x1 = ( 10 + 14) / 6 =4
x2 = ( 10 - 14) / 6 = - 4/6 = - 2/3
2) 9x^2 + 6x + 1 - x^2 + 4x - 4 = 0
8x^2 + 10x - 3 = 0
D = b^2 - 4a c = 100 + 96 = 196 = 14^2
x1 = ( - 10 + 14) / 16 = 0,25
x2 = ( -10 - 14) / 16 = - 1,5