F4 Quadratic equations

3x(x-3) = x-8
3x^2 - 9x = x-8
3x^2 - 10x + 8 = 0
(3x-4)(x-2) = 0
x = 4/3 or 2

12 - (x-4)(3x-12) = 0
3[4 - (x-4)(x-4)] = 0
4 - (x-4)^2 = 0
(x-4)^2 = 4
x-4 = 2 or -2
x = 6 or 2

(x-5)(2x+1)-(1+2x) = 0
(2x+1)(x-5-1) = 0
(2x+1)(x-6) = 0
x = -1/2 or 6

(a-2)(a+2) = (15/2)a
a^2 - 4 = (15/2)a
2a^2 - 15a - 8 = 0
(a-8)(2a+1) = 0
a = 8 or -1/2

(2x-5)^2 = (x-3)(6x-15)
(2x-5)^2 - 3(x-3)(2x-5) = 0
(2x-5) [(2x-5)-3(x-3)] = 0
(2x-5)(2x-5-3x+9) = 0
(2x-5)(-x+4) = 0
x = 5/2 or 4