Помогите 15 баллов даю а)5x^2+0,2x=0 б)5x^2-6x+1=0 в) 3x(3x-2)+7=6

Решите задачу:

$a)5 {x}^{2} + 0.2x = 0 \\ x(5x + 0.2) = 0 \\ x1 = 0 \\ 5x + 0.2 = 0 \\ x2 = - 0.2 \div 5 \\ x2 = - 0.04 \\ b)5 {x}^{2} - 6x + 1 = 0 \\ d = 36 - 20 = 16 \\ x1 = \frac{6 + 4}{10} = 1 \\ x2 = \frac{6 - 4}{10} = \frac{1}{5} = 0.2 \\ c)3x(3x - 2) + 7 = 6 \\ 9 {x}^{2} - 6x + 1 = 0 \\ ( {3x - 1)}^{2} = 0 \\ 3x - 1 = 0 \\ x = \frac{1}{3}$