Rozwiąż równanie: a. -7x2 + 42x = 0 b. 9x2 + 1/3x = 0 c. 36x2 = 6x d. 2x + 18x2 = 0 e. 100x2 - 81 = 0

a) - 7 x^2 + 42x = 0 |:(-7) x^2 - 6x = 0 x(x - 6) = 0 x = 0 v x = 6 b) 9 x^2 + 1/3 x = 0 |:9 x^2 + 1/27 x = 0 x(x + 1/27) = 0 x = 0 v x = - 1/27 c) 36 x^2 = 6x 36 x^2 - 6x = 0 |:36 x^2 - 1/6 x = 0 x(x - 1/6) = 0 x = 0 v x = 1/6 d) 2x + 18 x^2 = 0 18 x^2 + 2x = 0 |:18 x^2 + 1/9 x = 0 x(x + 1/9) = 0 x = 0 v x = - 1/9 e) 100 x^2 - 81 = 0 (10x - 9)(10x + 9) = 0 x = 9/10 v x = - 9/10