1. 25x^2 - 9 = 0
<=>(5x-3)(5x+3)=0
<=> x=3/5 hoặc x= -3/5
2. (x-3)^2 - 4 = 0
<=> (x-3-2)(x-3+2)=0
​<=> (x-5)(x-1)=0
​<=> x=5 hoặc x=1
3. x^2 - 2x = 24
​<=> x^2 - 2x - 24 = 0
​<=> x(x-6) + 4(x-6) = 0
​<=> (x+4)(x-6) = 0
​<=>  x=-4 hoặc x=6
4. (x+4)^2 - (x+1)(x-1) = 16
​<=> (x+4)^2 - 16 - x^2 + 1 = 0
​<=>  (x+4-4)(x+4+4) - x^2 + 1 = 0
​<=>  x(x+8) - x^2 + 1 = 0
​<=> x^2 + 8x - x^2 + 1 = 0
​<=>  x = -1/8
5. (2x-1)^2 + (x+3)^2 - 5(x+7)(x-7) = 0
​<=> 4x^2 - 4x + 1 + x^2 + 6x + 9 - 5x^2 + 245 = 0
​<=> 2x + 255 = 0
​<=> x = -255/2
6. 3(x-1)^2 - 3x(x-5) =1
​<=> 3x^2 - 6x + 3 - 3x^2 + 15x - 1 = 0
​<=> 9x + 2 = 0
​<=> x = -2/9
7. (6x-2)^2 + (5x-2)^2 - 4(3x-1)(5x-2) = 0
​<=> (5x-2)^2 - 2(6x-2)(5x-2) + (6x-2)^2 = 0
​<=> (6x - 2 - 5x + 2)^2 = 0
​<=> x^2=0
​<=> x=0
8. (x-2)^3 - x^2(x-6) = 4
​<=> x^3 - 8 - 6x^2 + 12x - x^3 + 6x - 4 = 0
​<=> -6x^2 + 18x - 12 = 0
​<=> -x^2 + 3x - 2 = 0
​<=> (x-1)(x-2)=0
​<=> x=1 hoặc x=2