a) x^2+2x-63=0

б) 0,9x-3x^2=0

в) 2x^2-5x+2=0

г) x^2-2x-6=0

а) х * * + 2 х - 63 = 0

х (х + 2) = 63

[x = 63 [x = 63

[x + 2 = 63 [x = 61

б) 0.9x - 3x * * = 0

3x (0.3 - x) = 0

[3x = 0 [x = 0

[0.3 - x = 0 [x = 0.3

в) 2 х * * - 5 х + 2 = 0

х (2 х - 5) = - 2

[x = - 2 [x = - 2

[2x - 5 = - 2 [x = 1.5

г) х * * - 2 х - 6 = 0

х (х - 2) = 6

[x = 6 [x = 6

[x - 2 = 6 [x = 8