4х²-8х+4=0 х²+6х-7=0 3х²+6х+3=0 х²+8х+16=0 18х²-9х=0

$4 {x}^{2} - 8x + 4 = 0 \div 4 \\ {x}^{2} - 2x + 1 = 0 \\ d = 4 - 4 = 0$

$x = \frac{2 + 0}{2} = \frac{2}{2} = 1$

${x}^{2} + 6x - 7 = 0 \\ d = 36 + 28 = 64 = 4 \\ x1 = \frac{ - 6 + 4}{2} = - \frac{2}{2} = - 1$

$x2 = \frac{ - 6 - 4}{2} = - \frac{10}{2} = - 5$

$3 {x}^{2} + 6x + 3 = 0 \div 3 \\ {x}^{2} + 2x + 1 = 0 \\ d = 4 - 4 = 0 \\ x = \frac{2 + 0}{2} = \frac{2}{2} = 1$

х=1

${x}^{2} + 8x + 16 = 0 \\ d = 64 - 64 = 0 \\ x = \frac{8 + 0}{2} = \frac{8}{2} = 4$

${18x}^{2} - 9x = 0 \\ 9x(2x - 1) = 0 \\ 9x = 0 \\ x = 0$

$2x - 1 = 0 \\ 2x = 1 \\ x = \frac{1}{2} = 0.5$